闲来无事,实现一个Javascript的数组删除或替换指定范围的方法(有原生splice可用)
思路
- 把截取范围后的元素向前移动,
- 然后删除长度范围之外的元素
Array.prototype.mySplice = function(start, end, newItem){
if(start > this.length || (end-start) < 0) return false;
if(end > this.length) {
end = this.length - 1;
}
var i = 0,
length = this.length,
endTmp = end;
for(; i< length; i++){
if(i >= start && endTmp < length){
if(newItem && i === start){
this[i] = newItem;
continue;
}
this[i] = this[endTmp++];
}
}
if(!newItem || end - start !== 1){
this.length -= end - start;
}
};
用法如下:
//替换指定元素
var arr1 = [1,2,3,4,5,6,6];
arr1.mySplice(1, 2, 100);
console.log(arr1); //[1, 100, 3, 4, 5, 6, 6]
//替换指定范围的元素
var arr2 = [1,2,3,4,5,6,6];
arr2.mySplice(1, 5, 100);
console.log(arr2);//[1, 100, 6]
//删除指定范围的元素
var arr3 = [1,2,3,4,5,6,6];
arr3.mySplice(1, 5);
console.log(arr3);//[1, 6, 6]