vino24

// 策略对象
const strategies = {
        isNonEmpty(value, errorMsg) {
            return value === '' ?
                errorMsg : void 0
        },
        minLength(value, length, errorMsg) {
            return value.length < length ?
                errorMsg : void 0
        },

vino24

const arrLike = {
    length: 4,
    2: "foo"
};
Array.from(arrLike); // [undefined, undefined, "foo", undefined] , length 是类数组对象必须的属性

// Array.from还可以接受一个映射函数作为第二个参数类似Array.map(..)
var arrLike = {
    length: 4,
    2: "foo"