splice 方法可以移除从 start 位置开始的指定个数的元素并插入新元素,从而修改 arrayObj。返回值是一个由所移除的元素组成的新 Array 对象。 要求 版本5.5 Js代码 Array.prototype.clear=function(){ this.length=0; } Array.prototype.insertAt=function(index,obj){ this.splice(index,0,obj); } Array.prototy...
// 拼接函数(索引位置, 要删除元素的数量, 元素) array.splice(2, 0,"three"); array;// 现在数组是这个样子 ["one", "two", "three", "four"] 如果你对扩展原生 JavaScript 不反感,那么可以将这个方法添加到数组原型(Array prototype)中: Array.prototype.insert =function (index, item) { this.spli...
array.concat(98) // returns [4, 10, 20, 37, 45, 98] 复制代码 1. 2. 3. 4. 5. 6. 算法: 将num插入arr。 将arr进行升序排序。 返回num的索引。 代码: function getIndexToIns(arr, num) { // Insert num into arr, creating a new array. let newArray = arr.concat(num) // [40, ...
代码: if(Array.isArray(value)){// 判断数组if(hasProto){protoAugment(value,arrayMethods)// 改写数组原型方法}else{copyAugment(value,arrayMethods,arrayKeys)}this.observeArray(value)//深度观察数组中的每一项}else{this.walk(value)// 重新定义对象类型数据}functionprotoAugment(target,src:Object){target...
element == element){ index = i; break; } obj = obj.next; } return index; } //清除所有元素 function clear(){ head = null; size = 0; } //属性转字符串 function getObjString(obj){ let str = ""; if (obj instanceof Array){ str += "["; for (let i = 0; i < obj.length...
If array destructuring is present, index-like properties in Array.prototype have not been overridden: Object.prototype[0] = 42; var [ a ] = []; var { 0: b } = {}; // 42 undefined console.log([][0], a); // 42 42 console.log({}[0], b); Earlier versions of JavaScript ...
Now, imagine that you're editingpages/index.jswhich contains: document.createElement(newButton({text:'Save'}).toDOMElement()); At this point,Buttonis undefined, so we need to import it. If you are used to doing this manually, this involves figuring out the path to the JavaScript module ...
The context for the template is an item in the my.vm.movies array. So by navigating up through the parent twice, the context will become the my.vm object. Then you can grab the movie with index 2 and use its boxArt.smallUrl property for the image. The result of this ...
[ 1 , 2 , 3 ].findindex( ( item )=> item=== 3 )) //2 如果数组中无值返回-1 includes(),find(),findindex()是es6的api 2.开始篇 [ 1 , 2 , 3 ].some( item => { return item=== 3 }) //true 如果不包含返回false 3.8、类二进...
The context for the template is an item in the my.vm.movies array. So by navigating up through the parent twice, the context will become the my.vm object. Then you can grab the movie with index 2 and use its boxArt.smallUrl property for the image. The result of this would be to ...