ES2015+ Walkthrough

New Builtin APIs

Part I

Strings

New Instance Methods

'blah'.includes('la');

'blah'.startsWith('bl');

'blah'.endsWith('la', 3);

'blah'.repeat(3);

'blah'.codePointAt(2);

Strings

New static Methods

String.fromCodePoint(97);

String.fromCodePoint(0x103);

String.fromCodePoint()

vs.

String.fromCharCode()

Template Strings

var user = 'gsklee';
var responseType = 'application/json';

console.log(
  `https://api.github.com/users/${user}
   Content-Type: ${responseType}`
);

Tagged Template Strings

var user = 'gsklee';

function GET () {
  return fetch(arguments[0].raw[0] + arguments[1])
         .then(function (response) {
           return response.json();
         });
}

GET `https://api.github.com/users/${user}`
.then(function (json) {
  console.log(json);
});

Strings

New static Methods

var user = 'gsklee';
var responseType = 'application/json';

function GET () {
  console.log(String.raw.apply(this, arguments));
}

GET `https://api.github.com/users/${user}
     Content-Type: ${responseType}`;

Numbers

Number.EPSILON;

Number.MAX_SAFE_INTEGER;

Number.MIN_SAFE_INTEGER;

New Properties

Numbers

Number.isFinite(Infinity);

Number.isInteger(Infinity);

Number.isNaN(0 / 0);

Number.isSafeInteger(Math.pow(2, 53) - 1);

Number.parseFloat('3.14');

Number.parseInt('3.14', 10);

New static Methods

Number.isFinite()

vs.

isFinite()

etc.

Binary & Octal Literals

0b1010101 === 85;

0o1010101 === 266305;

Maths

Math.acosh(1);
Math.asinh(1);
Math.atanh(1);
Math.cbrt(8);
Math.clz32(1);
Math.cosh(1);
Math.expm1(1);
Math.hypot(3, 4);
Math.imul(3, 4);
Math.log1p(1);
Math.log10(1);
Math.log2(1);
Math.sinh(1);
Math.tanh(1);

New static Methods

Maths

Math.fround(Math.PI);

Math.sign(-Infinity);

Math.trunc(42.84);

Math.trunc(-1.123);

New static Methods

Functions

function foo () {}.name;

/* Babel Only */

var bar = function () {};

bar.name;

New Instance Methods

Arrays

[1, 2, 3, 4, 5].copyWithin(1, 3);

[1, 2, 3, 4, 5].fill(42);

function finder (value) {
  return value === 5;
}

[1, 2, 3, 4, 5].find(finder);

[1, 2, 3, 4, 5].findIndex(finder);

New Instance Methods

Arrays

[1, 2, 3, 4, 5].includes(1);

New Instance Methods (ES2016)

Arrays

Array.of(42);

Array.from(document.querySelectorAll('a')).map(function (a) {
  return a.innerHTML;
});

function sum () {
  return Array.from(arguments).reduce(function (x, y) {
    return x + y;
  });
}

sum(1, 2, 3, 4, 5);

New static Methods

ES2015+ Walkthrough, Part I: New Builtin APIs

By G. Kay Lee

ES2015+ Walkthrough, Part I: New Builtin APIs

  • 2,897
Loading comments...

More from G. Kay Lee