var obj = [{ foo: 'bar', baz: 42 }, { foo: 'bar2', baz: 142 }];
forEach
obj.forEach((item, index) => { console.log(item) //{foo: "bar", baz: 42} ... console.log(index) //0 ... })
for in
for (const key in obj) { console.log(obj[key]) //{ foo: 'bar', baz: 42 } ... console.log(key) // 0 ... }
for of最适合遍历的是map对象,set对象
var maps = new Map() maps.set("key1", { name: "唐三", value: 123 }) maps.set("key2", { name: "番茄", value: 456 }) for (const [key, value] of maps) { console.log(key) //key1 ... console.log(value) // { name: "唐三", value: 123 } ... maps.delete('key1') } console.log(maps)
使用for of还需要记住3个Object的方法
Object.keys(),Object.values(),Object.entries()
Object.keys(),Object.values(),Object.entries() let { keys, values, entries } = Object; var obj = [{ foo: 'bar', baz: 42 }, { foo: 'bar2', baz: 142 }]; for (let key of keys(obj)) { console.log(key) } for (let key of Object.values(obj)) { console.log(key) } for (let key of entries(obj)) { console.log(key) }