let a = [1,2,3]; let b = [0, ...a, 4]; // [0,1,2,3,4] let obj = { a: 1, b: 2 }; let obj2 = { ...obj, c: 3 }; // { a:1, b:2, c:3 } let obj3 = { ...obj, a: 3 }; // { a:3, b:2 }
(二)剩余操作符(rest operator),是解构的一种
let a = [1,2,3]; let [b, ...c] = a; b; // 1 c; // [2,3] // 也可以 let a = [1,2,3]; let [b, ...[c,d,e]] = a; b; // 1 c; // 2 d; // 3 e; // undefined // 也可以 function test(a, ...rest){ console.log(a); // 1 console.log(rest); // [2,3] } test(1,2,3)
(三)
let object = { a: '01', b: '02' }; let newObject = { c: '03', ...object }; console.log(newObject); //{c: "03", a: "01", b: "02"}