数组

数组遍历

const ary = [1,6,89,78,,90];
        for(let i=0;i<ary.length;i++){
            // 过滤不存在，undefined,null
            if(!ary[i]) continue;
            // 过滤不存在和undefined
            if(ary[i]=== undefined) continue;
            // 只过滤不存在
            if(!(i in ary)) continue;
            console.log(ary[i])
        }

数组去重

var ary2 = ["apple",1,2,2,2,"banner","apple"];
        var unique = [];
        for(let i=0;i<ary2.length;i++){
            if(unique.indexOf(ary2[i])=== -1) {
            
                unique.push(ary2[i])
        }
    }

Array.prototype.uniq = function () {
    var result = [];
    var flag = true;
    for(var i =0;i<this.length;i++)
        {
            if(result.indexOf(this[i])==-1)
                {
                    if(this[i]!=this[i])
                        {
                            if(flag)
                                {
                                    result.push(this[i]);
                                    flag = false;
                                }
                        }
                    else
                        {
                            result.push(this[i]);
                        }
                }
        }
    return result;
}