ECMAScript 2015 - 2016 diff points

ECMAScript 2015 - 2016 diff points.md

ECMAScript 2015 - 2016 diff points

See also Normative commits: es2016-normative-changes.md

ES2016 Draft 1

• Word to Ecmarkup
  • .docx to .html

ES2016 Draft 2015-10-19

String.prototype.split has been reverted to ES5 semantics.

The limit parameter is now coerced using ToUint32 instead of ToLength.

• ES5 (15.5.4.14.5): If limit is undefined, let lim = 2**32-1; else let lim = ToUint32(limit).
• ES6 (21.1.3.17.8): If limit is undefined, let lim = 2**53-1; else let lim = ToLength(limit).

Notes: 6.12 String.prototype.split, its limit argument, and ToLength vs ToUint32 Commmits: Revert String.prototype.split's to ES5 behavior · tc39/ecma262@bfe9e11

Number, Boolean, and String prototypes are reverted to ES5 semantics

Number.prototype.valueOf(Number.prototype)

     <!-- es6num="19.3.3" -->
     <emu-clause id="sec-properties-of-the-boolean-prototype-object">
       <h1>Properties of the Boolean Prototype Object</h1>
-      <p>The Boolean prototype object is the intrinsic object %BooleanPrototype%. The Boolean prototype object is an ordinary object. It is not a Boolean instance and does not have a [[BooleanData]] internal slot.</p>
+      <p>The Boolean prototype object is the intrinsic object %BooleanPrototype%. The Boolean prototype object is an ordinary object. The Boolean prototype is itself a Boolean object; it has a [[BooleanData]] internal slot with the value *false*.</p>

ES2016 Draft 2015-11-03

ES2016 Draft 2015-12-01

early error of function tthat contain sloopy and strict.

• IsSimpleParameterList
• Strictness scoping - Google slide
• tc39-notes/july-29.md at master · tc39/tc39-notes
• tc39-notes/july-29.md at master · tc39/tc39-notes

Add Layer for Promise's unhandled rejection.

window.addEventListener('unhandledrejection', unhandled);
window.addEventListener('rejectionhandled', handled);

• HostPromiseRejectionTracker
• domenic/unhandled-rejections-browser-spec: Spec patches for HTML and ES for tracking unhandled promise rejections with events

Remove [[Construct]] from generators.

Disallow new generatorFunction();

function * g() { this.foo }
new g(); // throw error

• tc39-notes/july-28.md at master · tc39/tc39-notes
• tc39-notes/july-29.md at master · tc39/tc39-notes

ES2016 Draft 2015-12-10

Add Array.prototype.includes and TypedArray.prototype.includes.

Why use includess instead of contains?

• tc39/Array.prototype.includes: Spec, tests, reference implementation, and docs for ESnext-track Array.prototype.includes
• Introducing Break the Web: Array extra methods case // Speaker Deck

ES2016 Draft 2015-12-20

[[HostReportErrors]] and GetActiveScriptOrModule()

• I need a concept of "currently running script" · Issue #78 · tc39/ecma262
• Layering: track execution contexts' script/module by domenic · Pull Request #242 · tc39/ecma262

ES2016 Draft 2016-01-20

ES2016 Draft 2016-02-15

• Add ** exponentiation operator
• Make Object.prototype an Immutable Prototype Exotic Object
  • How should browsers mitigate Proxy-related security issues? · Issue #272 · tc39/ecma262
• Require Unicode 8
  • [ES2016] Require Unicode 8.0.0 · Pull Request #300 · tc39/ecma262 | ECMAScript Daily
• Array.prototype.indexOf now normalizes -0 to +0 when -0 is passed as the start index and the search string occurs at index 0

print("indexOf returns +0: " + (1/[true].indexOf(true, -0) > 0));
print("lastIndexOf returns +0: " + (1/[true].lastIndexOf(true, -0) > 0));

see also Improve TypedArray constructor/Proxy interaction by littledan · Pull Request #220 · tc39/ecma262

• Normative: Remove [[Enumerate]] and associated reflective capabilities by bterlson · Pull Request #367 · tc39/ecma262

Remove Proxy enumerate trap and Reflect.enumerate

• Why Remove Proxy [[Enumerate]] and Reflect.enumerate? | ECMAScript Daily