This table shows proposals which have not yet been included in the current ECMAScript standard, but are at one of the maturity stages of the TC39 process.
V8 SpiderMonkey JavaScriptCore Chakra Other
Minor difference (1 point) Small feature (2 points) Medium feature (4 points) Large feature (8 points)
Compilers/polyfills Desktop browsers Servers/runtimes Mobile
Feature name Current browser Traceur Babel +
core-js
[2]
Closure Type-
Script +
core-js
IE 11 Edge 12 Edge 13 Edge 14 Edge 15 Edge 16 Preview FF 45 ESR FF 47 FF 48 FF 49 FF 50 FF 51 FF 52 ESR FF 53 FF 54 FF 55 Beta FF 56 Nightly CH 51,
OP 38
[1]
CH 52,
OP 39
[1]
CH 53,
OP 40
[1]
CH 54,
OP 41
[1]
CH 55,
OP 42
[1]
CH 56,
OP 43
[1]
CH 57,
OP 44
[1]
CH 58,
OP 45
[1]
CH 59,
OP 46
[1]
CH 60,
OP 47
[1]
CH 61,
OP 48
[1]
SF 8 SF 9 SF 10 SF 10.1 SF 11 SF TP WK PJS Node 0.10[3] Node 0.12[3] io.js[3] Node 4[3] Node 5[3] Node 6.0-6.4[3] Node >=6.5 <7[3] Node 7.0-7.5[3] Node >=7.6 <8[3] Node 8[3] DUK 2.0 DUK 2.1 iOS 8 iOS 9 iOS 10.0-10.2 iOS >=10.3 <11 iOS 11
Candidate (stage 3)
§object rest/spread properties 0/2 2/2 0/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 2/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 2/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 1/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2
§object rest properties No Yes No Yes No No No No No No No No No No No No No No No Yes Yes No No No No No No No Flag Flag Yes Yes No No No No No No Yes No No No No No No No No No No Flag No No No No No No No
§object spread properties No Yes No Yes No No No No No No No No No No No No No No No Yes Yes No No No No No No No Flag Flag Yes Yes No No No No No No No No No No No No No No No No No Flag No No No No No No No
§global 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 1/2 1/2 1/2 1/2 1/2 1/2 1/2 1/2 1/2 0/2 0/2 2/2 0/2 0/2 0/2 0/2 0/2
§"global" global property is global object No No No No No No No No No No No No No No No No No No[4] No[4] No[4] No[4] No No No No No No No No No No No No No No No No No[5] No[5] No Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes No No No No No
§"global" global property has correct property descriptor No No No No No No No No No No No No No No No No No No[4] No[4] No[4] No[4] No No No No No No No No No No No No No No No No No[5] No[5] No No No No No No No No No No No No Yes No No No No No
§Asynchronous Iterators 0/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2
§async generators No Yes No No No No No No No No No No No No No No No No No No[6] No[6] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§for-await-of loops No Yes No No No No No No No No No No No No No No No No No No[6] No[6] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§RegExp named capture groups No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No Flag No No No No No No No No No No No No No No No No No No No No No No No No No
§s (dotAll) flag for regular expressions ? ? ? ? No No No No No No No No No No No No No No No No No ? ? ? ? ? ? ? ? ? ? Flag ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
§RegExp Lookbehind Assertions No No No No No No No No No No No No No No No No No No No No No Flag Flag Flag Flag Flag Flag Flag Flag Flag Flag Flag No No No No No No No No No No No No No Flag Flag Flag Flag Flag No No No No No No No
§RegExp Unicode Property Escapes No No No No No No No No No No No No No No No No No No No No No No No No No No No No No Flag Flag Flag No No No No No No No No No No No No No No No No No No No No No No No No No
§Function.prototype.toString revision MDN (Mozilla Development Network) logo  0/7 0/7 0/7 0/7 1/7 1/7 2/7 4/7 4/7 4/7 1/7 1/7 1/7 1/7 1/7 2/7 2/7 2/7 5/7 7/7 7/7 4/7 4/7 4/7 4/7 4/7 4/7 4/7 4/7 4/7 4/7 4/7 1/7 1/7 4/7 4/7 4/7 4/7 4/7 1/7 0/7 0/7 0/7 4/7 4/7 4/7 4/7 4/7 4/7 4/7 1/7 1/7 1/7 1/7 4/7 4/7 4/7
§functions created with the Function constructor No No No No No No No No No No No No No No No No No No Yes Yes Yes No No No No No No No No Flag Flag Flag No No No No No No No No No No No No No No No No No No No No No No No No No
§arrows No No No No No No Yes Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes
§[native code] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§class expression with implicit constructor No No No No No No No Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes
§class expression with explicit constructor No No No No No No No Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes
§unicode escape sequences in identifiers No No No No No No No No No No No No No No No No No No Yes Yes Yes No No No No No No No No Flag Flag Flag No No No No No No No No No No No No No No No No No No No No No No No No No
§methods and computed property names No No No No No No No No No No No No No No No No No No Yes Yes Yes No No No No No No No No Flag Flag Flag No No No No No No No No No No No No No No No No No No No No No No No No No
Draft (stage 2)
§Generator function.sent Meta Property No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Class and Property Decorators 0/1 0/1 0/1 1/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1
§class decorators No No[7] No Yes No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§string trimming 0/4 4/4 0/4 4/4 0/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 0/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 2/4 0/4 0/4 2/4 2/4 2/4 2/4 2/4
§String.prototype.trimLeft MDN (Mozilla Development Network) logo  No Yes No Yes[8] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes
§String.prototype.trimRight MDN (Mozilla Development Network) logo  No Yes No Yes[8] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes
§String.prototype.trimStart No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§String.prototype.trimEnd No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§class fields 1/3 1/3 0/3 1/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3
§class properties Yes Yes No Yes No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§private fields basic support No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§private fields initializers No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
Proposal (stage 1)
§do expressions No Yes No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§SIMD (Single Instruction, Multiple Data) MDN (Mozilla Development Network) logo  0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57 0/57
§basic support MDN (Mozilla Development Network) logo  No No No No No Flag[9] Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§Float32x4 MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§Int32x4 MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§Int16x8 MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§Int8x16 MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§Uint32x4 MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§Uint16x8 MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§Uint8x16 MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§Bool32x4 MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§Bool16x8 MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§Bool8x16 MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%floatType%.abs MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.add MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%integerType%.addSaturate MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.and MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%booleanType%.anyTrue MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%booleanType%.allTrue MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.check MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.equal MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.extractLane MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.greaterThan MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.greaterThanOrEqual MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.lessThan MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.lessThanOrEqual MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.mul MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%floatType%.div MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.load MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.load1 MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.load2 MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.load3 MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%floatType%.max MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%floatType%.maxNum MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] No No No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%floatType%.min MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%floatType%.minNum MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] No No No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.neg MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.not MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.notEqual MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.or MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%floatType%.reciprocalApproximation MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%floatType%.reciprocalSqrtApproximation MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.replaceLane MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.select MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%integerType%.shiftLeftByScalar MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%integerType%.shiftRightByScalar MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.shuffle MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.splat MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%floatType%.sqrt MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.store MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.store1 MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.store2 MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.store3 MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.sub MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%integerType%.subSaturate MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.swizzle MDN (Mozilla Development Network) logo  No No No No No No Flag[9] Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.xor MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.fromTIMDBits MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§SIMD.%type%.fromTIMD MDN (Mozilla Development Network) logo  No No No No No No No Flag[9] Flag[9] Flag[9] No No No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] No[6] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No No No No No
§Realms No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Observable 0/8 8/8 0/8 8/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8
§basic support No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Symbol.observable well known symbol No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Observable.prototype.subscribe No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Observable constructor behavior No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Observable.prototype.forEach No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Observable.prototype[Symbol.observable] No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Observable.of No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Observable.from No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§String.prototype.matchAll No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§weak references No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Frozen Realms API No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
Strawman (stage 0)
§bind (::) operator 0/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2
§binary form No Yes No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§unary form No Yes No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§String.prototype.at No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§additional meta properties 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3
§function.callee No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§function.count No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§function.arguments No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§method parameter decorators No No No Yes No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§function expression decorators No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Reflect.isCallable / Reflect.isConstructor 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2
§Reflect.isCallable No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Reflect.isConstructor No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§zones 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7
§Zone No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Zone.current No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Zone.prototype.name No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Zone.prototype.parent No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Zone.prototype.fork No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Zone.prototype.run No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Zone.prototype.wrap No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§asap No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§syntactic tail calls 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2
§direct recursion No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§mutual recursion No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
Pre-strawman
§Metadata reflection API 0/9 9/9 0/9 9/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9
§Reflect.defineMetadata No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Reflect.hasMetadata No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Reflect.hasOwnMetadata No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Reflect.getMetadata No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Reflect.getOwnMetadata No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Reflect.getMetadataKeys No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Reflect.getOwnMetadataKeys No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Reflect.deleteMetadata No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No
§Reflect.metadata No Yes No Yes[8] No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No

[1] Flagged features have to be enabled via "Experimental Javascript features" flag unless otherwise stated

[2] Flagged features require an optional transformer setting.

[3] Flagged features have to be enabled via --harmony or --es_staging flag

[4] The feature was disabled due to some compatibility issues.

[5] The feature was disabled due to compatibility issues.

[6] The feature is enabled by default only in Firefox Nightly.

[7] Babel 6 still has no official support decorators, but you can use this plugin.

[8] This feature is supported when using TypeScript with core-js, or when a native ES6 host is used.

[9] Flagged features have to be enabled via "Enable experimental Javascript features" setting under about:flags

[10] The feature have to be enabled via --js-flags="--harmony-simd" flag