js 中连续的 3 个点 three dots (...) in javascript

这个叫扩展运算符

https://dev.to/sagar/three-dots---in-javascript-26ci

5 种用法

function myFunc(...[x, y, z]) {

  return x * y* z;

}

myFunc(1)          // NaN

myFunc(1, 2, 3)    // 6

myFunc(1, 2, 3, 4) // 6 (fourth parameter is not destructured)

function myFunc(x, y, ...params) { // used rest operator here

  console.log(x);

  console.log(y);

  console.log(params);

}

var inputs = ["a", "b", "c", "d", "e", "f"];

myFunc(...inputs); // used spread operator here

// "a"

// "b"

// ["c", "d", "e", "f"]

const featured = ['Deep Dish', 'Pepperoni', 'Hawaiian'];

const specialty = ['Meatzza', 'Spicy Mama', 'Margherita'];

const pizzas = [...featured, 'veg pizza', ...specialty];

console.log(pizzas); // 'Deep Dish', 'Pepperoni', 'Hawaiian', 'veg pizza', 'Meatzza', 'Spicy Mama', 'Margherita'

var obj1 = { foo: 'bar', x: 42 };

var obj2 = { foo: 'baz', y: 13 };

var clonedObj = { ...obj1 };

// Object { foo: "bar", x: 42 }

var mergedObj = { ...obj1, ...obj2 };

// Object { foo: "baz", x: 42, y: 13 }

[a, b, ...rest] = [10, 20, 30, 40, 50];

console.log(rest); // [30,40,50]

let {a, b, ...rest} = {a: 10, b: 20, c: 30, d: 40}

console.log(a); // 10

console.log(b); // 20

console.log(rest); // { c: 30, d: 40 }

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js 中连续的 3 个点 three dots (...) in javascript

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