ECMAScript 7 is the next evolution of the ECMA-262 standard, this is at a very early stage, you may want to checkout paws-on-es6 and jsfeatures.in as well.

List of ES7 features:

Exponentiation Operator
Async functions
Async generators
Object.getOwnPropertyDescriptors
Object.values
Object.entries
Array.prototype.includes
Typed Objects
Trailing commas in function syntax.
Class decorators.
Class properties
Map.prototype.toJSON
Set.prototype.toJSON
String.prototype.at
Object rest properties
Object spread properties
String.prototype.padLeft
String.prototype.padRight
String.prototype.trimLeft
String.prototype.trimRight
Regexp.escape
Bind Operator
Reflect.Realm

Exponentiation Operator

Performs exponential calculation on operands. Same algorithm as Math.pow(x, y)

Stage: Draft.

let cubed = x => x ** 3;

cubed(2) // 8;

Async functions

Deferred Functions

Stage: Proposal.

function wait(t){
  return new Promise((r) => setTimeout(r, t));
}

async function asyncMania(){
  console.log("1");
  await wait(1000);
  console.log("2");
}

asyncMania()
.then(() => console.log("3"));

// logs: 1 2 3

Async generators

Deferred generators.

Stage: Proposal.

// provider
async function* nums() {
  yield 1;
  yield 2;
  yield 3;
}

// consumer
async function printData() {
  for(var x on nums()) {
    console.log(x);
  }
}

Object.getOwnPropertyDescriptors

Returns a property descriptor for an own property.

Stage: Strawman.

// Creating a shallow copy.
var shallowCopy = Object.create(
  Object.getPrototypeOf(originalObject),
  Object.getOwnPropertyDescriptors(originalObject)
);

Object.values

Get all the values of the object as an array.

Stage: Shall reach Strawman

var person = { fname: "Hemanth", lname: "HM", location: "Earth", type: "Human" };

Object.values(person);

//^ ["Hemanth","HM","Earth","Human"]

Object.entries

Returns a Array of arrays of key,value pairs.

Stage: Shall reach Strawman

var person = { fname: "Hemanth", lname: "HM", location: "Earth", type: "Human" };

Object.entries(person);

//^ [["fname","Hemanth"],["lname","HM"],["location","Earth"],["type","Human"]]

Array.prototype.includes

Determines whether an array includes a certain element or not.

Stage: Draft.

[1, 2, 3].includes(3, 0, 7); // true
[1, 2, NaN].includes(NaN); // true
[0,+1,-1].includes(42); // false

Typed Objects

Portable, memory-safe, efficient, and structured access to contiguously allocated data.

Stage: Proposal.

var Point = new StructType({
  x: int32,
  y: int32
});

var point = new Point({
  x: 42,
  y: 420
});

Trailing commas in function syntax.

Trailing commas in parameter and argument lists.

Stage: Proposal

var meow = function (cat1, cat2,) {}

Math.max(4,2,0,);

Class decorators.

Annotate and modify classes and properties at design time.

Stage: Proposal.

class Person {
  @cantEnum
  get kidCount() { return this.children.length; }
}

function cantEnum(target, name, descriptor) {
  descriptor.enumerable = false;
  return descriptor;
}

Class properties

Properties of class.

Stage: Strawman.

class Cat {
  name = 'Garfield';
  static says = 'meow';
}
new Cat().name; // Garfield
Cat.says; // meow

Map.prototype.toJSON

toJSON for Maps.

Stage: Strawman.

var myMap = new Map();
myMap.set(NaN, "not a number");

console.log(myMap.toJSON()); // {"NaN":"not a number"}

Set.prototype.toJSON

toJSON for Sets.

Stage: Strawman.

var mySet = new Set();
mySet.add(NaN);
mySet.add(1);
console.log(mySet.toJSON()) // {"1":1,"NaN":null}

String.prototype.at

String containing the code point at the given position

Stage: Strawman.

'abc\uD834\uDF06def'.at(1) // 'b'
'abc\uD834\uDF06def'.at(3) // '\uD834\uDF06'

Object rest properties

Rest properties for object destructuring assignment.

Stage: Strawman.

let { fname, lname, ...rest } = { fname: "Hemanth", lname: "HM", location: "Earth", type: "Human" };
fname; //"Hemanth"
lname; //"HM"
rest; // {location: "Earth", type: "Human"}

Object spread properties

Spread properties for object destructuring assignment.

Stage: Strawman.

let info = {fname, lname, ...rest};

info; // { fname: "Hemanth", lname: "HM", location: "Earth", type: "Human" }

String.prototype.padLeft

left justify and pad strings.

Stage: Strawman.

"hello".padLeft(4)            #=> "hello"
"hello".padLeft(20)           #=> "hello               "
"hello".padLeft(20, '1234')   #=> "hello123412341234123"

String.prototype.padRight

right justify and pad strings.

Stage: Strawman.

"hello".padRight(4)            #=> "hello"
"hello".padRight(20)           #=> "               hello"
"hello".padRight(20, '1234')   #=> "123412341234123hello"

String.prototype.trimLeft

left trims the string.

Stage: Candidate.

' \t \n LeftTrim   \t\n'.trimLeft(); // 'LeftTrim   \t\n';

String.prototype.trimRight

right trims the string.

Stage: Candidate.

' \t \n RightTrim   \t\n'.trimRight(); // ' \t \n RightTrim';

Regexp.escape

Escapes any characters that would have special meaning in a regular expression.

Stage: Strawaman

RegExp.escape("(*.*)"); // "\(\*\.\*\)"
RegExp.escape("｡^･ｪ･^｡") // "｡\^･ｪ･\^｡"
RegExp.escape("😊 *_* +_+ ... 👍"); // "😊 \*_\* \+_\+ \.\.\. 👍"

Bind Operator

:: Function binding and method extraction

Stage: Shall reach Strawman.

let log = (level, msg) => ::console[level](msg);

import { map, takeWhile, forEach } from "iterlib";

getPlayers()
  ::map(x => x.character())
  ::takeWhile(x => x.strength > 100)
  ::forEach(x => console.log(x));

Reflect.Realm

TDB

ldfaiztt / es7-features Goto Github PK

es7-features's Introduction

Exponentiation Operator

Async functions

Async generators

Object.getOwnPropertyDescriptors

Object.values

Object.entries

Array.prototype.includes

Typed Objects

Trailing commas in function syntax.

Class decorators.

Class properties

Map.prototype.toJSON

Set.prototype.toJSON

String.prototype.at

Object rest properties

Object spread properties

String.prototype.padLeft

String.prototype.padRight

String.prototype.trimLeft

String.prototype.trimRight

Regexp.escape

Bind Operator

Reflect.Realm

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