1. Decorators

    ECMAScript Decorators are an in-progress proposal for extending JavaScript classes. Decorators use a special syntax, prefixed with an `@` symbol and placed immediately before the code being extended.

  2. csstransformvalue api: [symbol.iterator]

  3. formdata api: [symbol.iterator]

  4. javascript built-in: intl: datetimeformat: `datetimeformat()` constructor: supports normative optional `chaindatetimeformat` behavior

  5. javascript built-in: intl: numberformat: `numberformat()` constructor: supports normative optional `chainnumberformat` behavior

  6. javascript built-in: symbol: for

  7. javascript built-in: symbol: keyfor