一、length JavaScript中Array的length属性非常有特点一一它不是只读的。因此,通过设置这个属性可以从数组的末尾移除项或添加新项,请看下面例子: 1 var colors = ["red", "blue", "grey"]; //创建一个包含3个字符串的数组 2 colors.length = 2; 3 console.log(colors[2]); /
> let array = ["a", "b", "c"]; > array.pop(); 'c' > array; [ 'a', 'b' ]Using delete creates empty spotsWhatever you do, don't use delete to remove an item from an array. JavaScript language specifies that arrays are sparse, i.e., they can have holes in them....
JavaScript Code : // Source: https://bit.ly/3hEZdCl// Function to compact an object by removing falsy values (null, false, 0, '', undefined)constcompactObject=val=>{// Use ternary operator to filter out falsy values for arrays, otherwise use the provided valueconstdata=Array.isArray(val...
map.values()—— 遍历并返回所有的值(returns an iterable for values), map.entries()—— 遍历并返回所有的实体(returns an iterable for entries)[key, value],for..of在默认情况下使用的就是这个。 这个有点像是对象中的那三个方法。 Map 与 Object 的转换 Object to Map Object.entries 代码语言:jav...
valueOf//继承自 object String String对象是文本值的包装器。除了存储文本,String对象包含一个属性和各种 方法来操作或收集有关文本的信息,String对象不需要进行实例化便能够使用。 String对象只有一个只读的length属性用于返回字符串的长度。 包装对象 除了上面三个对象,Javascript 还拥有 Date、Array、Math 等内置对象...
setLegs(legs) { if (!Array.isArray(legs)) { thrownewError('"legs" is not an array') } this.legs = legs returnthis } setScent(scent) { this.scent = scent returnthis } updateTongueWidthFieldName(tongue) { constnewTongue= { ...tongue } delete newTongue['tongueWidth'] ...
Delete an object from the bucket. parameters: name {String} object name store on OSS [options] {Object} optional parameters [timeout] {Number} the operation timeout [versionId] {String} the version id of history object Success will return the info contains response. object: res {Object} ...
firstconstsecond=newMap([[1,"uno"],[2,"dos"],]);// Map 对象同数组进行合并时,如果有重复的键值,则后面的会覆盖前面的。constmerged=newMap([...first,...second,[1,"eins"]]);console.log(merged.get(1));// einsconsole.log(merged.get(2));// dosconsole.log(merged.get(3));// thre...
--- String --- Array [ "India", "Russia" ] --- Number --- Array(4) [ 1, 3, 5, 7 ] --- Object --- Name: Bheem, Age: 25 Name: Nakul, Age: 23 Remove from Array with delete Operator JavaScript delete operator removes a property from an object and becomes undefined. When d...
arrayObj.splice(deletePos,deleteCount); //删除从指定位置deletePos开始的指定数量deleteCount的元素,数组形式返回所移除的元素 5. 数组的截取和合并 1 2 3 4 5 arrayObj.slice(start, [end]); //以数组的形式返回数组的一部分,注意不包括 end 对应的元素,如果省略 end 将复制 start 之后的所有元素 ...