Question

js中判断数组中是否含有某个字符串方法

Answer 1

if (!('includes' in [])) {
    Array.prototype.includes = function(value) {
        var self = this
        for (var i = 0; i < this.length; i++) {
            if (self[i] === value) {
                return true
            } else {
                return false
            }
        }
    }
}

[1,2,3,4,65,67,89,4].includes(67)
// true
[1,2,3,4,65,67,89,4].includes(88)
// false