1.new Set()
let arr = [1, 2, 2, 3];
let set = new Set(arr);
let newArr = Array.from(set); // Array.from將Set結(jié)構(gòu)轉(zhuǎn)換成數(shù)組
console.log(newArr) // [1, 2, 3]
2.Object.assign()
let obj1 = {a: 1};
let obj2 = {b: 2};
let obj3 = Object.assign({}, obj1, obj2);
console.log(obj3); // {a: 1, b: 2}
3.map()
let arr3 = [1, 2, 3, 4, 5];
let newArr3 = arr3.map((e, i) => e * 10); // 給數(shù)組每一項(xiàng)乘以10
console.log(newArr3); // [10, 20, 30, 40, 50]
4.filter()
let arr4 = [1, 2, 3, 4, 5];
let newArr4 = arr4.filter((e, i) => e % 2 === 0); // 取模,過(guò)濾余數(shù)不為0的數(shù)
console.log(newArr4); // [2,4]
5.some()
let arr5 = [{result: true}, {result: false}];
let newArr5 = arr5.some((e, i) => e.result); // 只要一個(gè)為true,即為true
console.log(newArr5); // true
6.every()
let arr6 = [{result: true}, {result: false}];
let newArr6 = arr6.every((e, i) => e.result); // 只要一個(gè)為false,即為false
console.log(newArr6); // false
7.~~運(yùn)算符
符號(hào)用在JavaScript中有按位取反的作用,~即是取反兩次,而位運(yùn)算的操作值要求是整數(shù),其結(jié)果也是整數(shù),所以經(jīng)過(guò)位運(yùn)算的都會(huì)自動(dòng)變成整數(shù),可以巧妙的去掉小數(shù)部分,類似于parseInt,比如:
let a = 1.23;
let b = -1.23;
console.log(~~a); // 1
console.log(~~b); // -1
8.||設(shè)置默認(rèn)值
let c = 1;
let d = c || 2; // 如果c的值為true則取存在的值,否則為2
console.log(d); // 1
9. ...運(yùn)算符
…運(yùn)算符是ES6中用于解構(gòu)數(shù)組的方法,可以用于快速獲取數(shù)組的參數(shù),比如:
let [num1, ...nums] = [1, 2, 3];
console.log(num1); // 1
console.log(nums); // [2, 3]
10.三元運(yùn)算符
let e = true,
f = '';
if (e) {
f = 'man';
} else {
f = 'woman';
}
// 等同于
e ? f = 'man' : f = 'woman';