data-common.json

{
  "babel": {
    "corejs": {
      "val": true,
      "note_id": "babel-core-js",
      "note_html": "This feature is supported when using Babel with <a href='https://github.com/zloirock/core-js'>core-js</a>."
    },
    "optional": {
      "val": "flagged",
      "note_id": "babel-optional-flag",
      "note_html": "This feature features requires an optional transformer setting."
    },
    "regenerator": {
      "val": true,
      "note_id": "babel-regenerator",
      "note_html": "This feature requires native generators or <code>regenerator-runtime</code>, it's a part of <code>babel-polyfill</code> or <code>babel-runtime</code>."
    }
  },
  "typescript": {
    "corejs": {
      "val": true,
      "note_id": "typescript-core-js",
      "note_html": "This feature is supported when using TypeScript with <a href='https://github.com/zloirock/core-js'>core-js</a>."
    },
    "fallthrough": {
      "val": "needs-polyfill-or-native",
      "note_id": "typescript-es6",
      "note_html": "TypeScript&apos;s compiler will accept code using this feature if the <code>--target ES6</code> flag is set, but passes it through unmodified and does not supply a runtime polyfill."
    },
    "downlevelIteration": {
      "val": true,
      "note_id": "typescript-downlevel-iteration",
      "note_html": "Requires the <code>downlevelIteration</code> compile option."
    },
    "notDownlevelIteration": {
      "val": false,
      "note_id": "typescript-not-downlevel-iteration",
      "note_html": "Does not work with the <code>downlevelIteration</code> compile option."
    }
  },
  "edge": {
    "experimental": {
      "val": "flagged",
      "note_id": "edge-experimental-flag",
      "note_html": "Flagged features have to be enabled via \"Enable experimental Javascript features\" setting under <code>about:flags</code>"
    }
  },
  "firefox": {
    "sharedmem": {
      "val": "flagged",
      "note_id": "firefox-sharedmem",
      "note_html": "The feature has to be enabled via <code>javascript.options.shared_memory</code> setting under <code>about:config</code>.  It is enabled by default in Firefox Developer Edition and Firefox Nightly builds."
    },
    "nomob": {
      "val": "flagged",
      "note_id": "firefox-nomob",
      "note_html": "The feature is available on desktop versions only, it is not available on mobile versions yet."
    },
    "beta": {
      "val": "flagged",
      "note_id": "firefox-beta",
      "note_html": "The feature is available only in Firefox Beta, Firefox Developer Edition and Firefox Nightly builds."
    },
    "developer": {
      "val": "flagged",
      "note_id": "firefox-developer",
      "note_html": "The feature is available only in Firefox Developer Edition and Firefox Nightly builds."
    },
    "nightly": {
      "val": "flagged",
      "note_id": "firefox-nightly",
      "note_html": "The feature is available only in Firefox Nightly builds."
    },
    "bigint": {
      "val": "flagged",
      "note_id": "firefox-bigint",
      "note_html": "The feature has to be enabled via <code>javascript.options.bigint</code> setting under <code>about:config</code>."
    },
    "classFields": {
      "val": "flagged",
      "note_id": "firefox-class-fields",
      "note_html": "The feature has to be enabled via <code>javascript.options.experimental.fields</code> setting under <code>about:config</code>."
    },
    "privateFields": {
      "val": "flagged",
      "note_id": "fx-private-fields",
      "note_html": "The feature has to be enabled via <code>javascript.options.experimental.private_fields</code> setting under <code>about:config</code>."
    },
    "privateClassFields": {
      "val": false,
      "note_id": "firefox-private-class-fields",
      "note_html": "The feature has to be enabled via <code>javascript.options.experimental.fields</code> setting under <code>about:config</code>. Private fields are supported by parser, but behave as public fields."
    }
  },
  "chrome": {
    "sharedmem": {
      "val": "flagged",
      "note_id": "chrome-sharedmem",
      "note_html": "The feature has to be enabled via \"Experimental enabled SharedArrayBuffer support in JavaScript.\" setting under <code>about:flags</code>"
    },
    "experimental": {
      "val": "flagged",
      "note_id": "chrome-experimental",
      "note_html": "The feature has to be enabled via \"Experimental Javascript features\" setting under <code>about:flags</code>"
    },
    "harmony": {
      "val": "flagged",
      "note_id": "chrome-harmony",
      "note_html": "The feature has to be enabled via <code>--js-flags=\"--harmony\"</code> flag"
    },
    "tco": {
      "val": false,
      "note_id": "chrome-tco",
      "note_html": "The feature is considered unstable, but can be enabled via <code>--js-flags=\"--harmony-tailcalls\"</code> flag"
    },
    "promise": {
      "val": false,
      "note_id": "chrome-promise",
      "note_html": "The feature is considered unstable, but can be enabled via <code>--js-flags=\"--harmony-promise-finally\"</code> flag"
    },
    "simd": {
      "val": false,
      "note_id": "chrome-simd",
      "note_html": "The feature is considered unstable, but can be enabled via <code>--js-flags=\"--harmony-simd\"</code> flag"
    },
    "stringPrototypeReplaceAll": {
      "val": "flagged",
      "note_id": "chrome-string-prototype-replace-all",
      "note_html": "The feature is considered unstable, but can be enabled via <code>--js-flags=\"--harmony-string-replaceall\"</code> flag"
    }
  },
  "safari": {
    "templateStringsPermanentCaching": {
      "val": false,
      "note_id": "safari-templ-cahing",
      "note_html": "Safari 12 caches TemplateStrings using a GC-able \"CodeBlock\". But TemplateStrings are supposed to always be identical! When the CodeBlock is reclaimed, the TemplateStrings' identity is broken. Thankfully, <code>[[Call]]</code> vs <code>[[Construct]]</code> generate different CodeBlocks, which exposes the <a href='https://bugs.webkit.org/show_bug.cgi?id=190756'>broken behavior.</a>"
    }
  },
  "graalvm": {
    "es6flag": {
      "val": "flagged",
      "note_id": "graalvm-js-ecmascript-version-6",
      "note_html": "Requires the <code>--js.ecmascript-version=6</code> flag."
    },
    "es2020flag": {
      "val": "flagged",
      "note_id": "graalvm-js-ecmascript-version-2020",
      "note_html": "Requires the <code>--js.ecmascript-version=2020</code> flag."
    },
    "es2021flag": {
      "val": "flagged",
      "note_id": "graalvm-js-ecmascript-version-2021",
      "note_html": "Requires the <code>--js.ecmascript-version=2021</code> flag."
    },
    "es2022flag": {
      "val": "flagged",
      "note_id": "graalvm-js-ecmascript-version-2022",
      "note_html": "Requires the <code>--js.ecmascript-version=2022</code> flag."
    },
    "esStagingFlag": {
      "val": "flagged",
      "note_id": "graalvm-js-ecmascript-version-staging",
      "note_html": "Requires the <code>--js.ecmascript-version=staging</code> flag."
    },
    "newSetMethodsFlag": {
      "val": "flagged",
      "note_id": "graalvm-experimental-options-js-new-set-methods",
      "note_html": "Requires the <code>--experimental-options --js.new-set-methods</code> flags."
    },
    "v8CompatFlag": {
      "val": "flagged",
      "note_id": "graalvm-experimental-options-js-v8-compat",
      "note_html": "Requires the <code>--experimental-options --js.v8-compat</code> flags."
    },
    "nashornCompatFlag": {
      "val": "flagged",
      "note_id": "graalvm-experimental-options-js-nashorn-compat",
      "note_html": "Requires the <code>--experimental-options --js.nashorn-compat</code> flags."
    },
    "globalPropertyFlag": {
      "val": "flagged",
      "note_id": "graalvm-experimental-options-js-global-property",
      "note_html": "Requires the <code>--experimental-options --js.global-property</code> flags."
    }
  },
  "hermes": {
    "xEs6PromiseFlag": {
      "val": "flagged",
      "note_id": "hermes-promise",
      "note_html": "The feature can be enabled via <code>-Xes6-promise</code> flag"
    },
    "xEs6SymbolFlag": {
      "val": "flagged",
      "note_id": "hermes-symbol",
      "note_html": "The feature can be enabled via <code>-Xes6-symbol</code> flag"
    },
    "xEs6ProxyFlag": {
      "val": "flagged",
      "note_id": "hermes-proxy",
      "note_html": "The feature can be enabled via <code>-Xes6-proxy</code> flag"
    },
    "evalStrictMode": {
      "val": false,
      "note_id": "hermes-eval-strict-mode",
      "note_html": "Hermes isn't supporting strict mode in eval, test result is unrepresentative. See <a href=\"https://github.com/facebook/hermes/issues/102#issuecomment-528489267\">this comment</a> for details"
    },
    "evalLexicalScopeFailed": {
      "val": false,
      "note_id": "hermes-eval-lexical-scope-failed",
      "note_html": "Hermes isn't supporting lexical scope in eval"
    },
    "evalLexicalScopeSuccess": {
      "val": true,
      "note_id": "hermes-eval-lexical-scope-success",
      "note_html": "Hermes isn't supporting lexical scope in eval, test result is unrepresentative"
    },
    "catchDestructuring": {
      "val": false,
      "note_id": "hermes-catch-destructuring",
      "note_html": "Hermes isn't currently supporting destructuring in catch parameters"
    },
    "class": {
      "val": false,
      "note_id": "hermes-class",
      "note_html": "Hermes isn't currently supporting classes apparently"
    }
  },
  "sparseNote": {
    "val": true,
    "note_id": "sparse_arrays",
    "note_html": "Internet Explorer 6 - 8 do not differentiate between a dense array with undefined values, and a sparse array. Specifically, <code>`0 in [,]`</code> and <code>`0 in [undefined]`</code> both yield false - whereas in a compliant browser, the former would give `false`, the latter `true`. As such, ES5 array iteration methods can only be shimmed reliably when dealing with dense arrays."
  }
}