使用 delete 操作符删除数组总某项元素时，被删除的元素会从该数组中删除，但是数组的 length 并不会改变 var arr = [1, 2, 3];delete arr[1]console.log(arr); // [1, undefined × 1, 2]console.log(delete arr[1]) // trueconsole.log(arr[1]); // undefined 但是这里存在一个问题 console....
bar); //undefined 删除数组元素 当你删除一个数组元素时,数组的长度(length)不受影响。即便你删除了数组的最后一个元素也是如此。 当用delete 运算符删除一个数组元素时,被删除的元素已经不再属于该数组。下面的例子中用 delete 删除了 trees[3]。 jsCopy to Clipboard const trees = ["redwood", "bay",...
console.log(Array.forEach); // 内置函数 delete Array.forEach // 不用区分严格模式与否 console.log(Array.forEach); // undefined Object.defineProperty() 设置为不可设置的属性,不可删除 var person = {}; Object.defineProperty(person, 'name', { value: '张三', configurable: false }) delete ...
console.log(Array.prototype.join); // 非严格模式下,join方法依然存在 需要注意的是,只是这些内置对象的属性不可删除,内置对象的方法是可以删除的,比如: console.log(Array.forEach); // 内置函数 delete Array.forEach // 不用区分严格模式与否 console.log(Array.forEach); // undefined Object.definePropert...
console.log(Array.forEach);// 内置函数deleteArray.forEach// 不用区分严格模式与否console.log(Array.forEach);// undefined Object.defineProperty()设置为不可设置的属性,不可删除 varperson = {};Object.defineProperty(person,'name', {value:'张三',configurable:false})deleteperson.name// 严格模式下,抛...
const person = { name: 'John', age: 30, occupation: 'Developer' }; console.log(person.name); // John delete person.name; console.log(person.name); // undefined This code removes the name property from the person object. After deletion, accessing the property returns undefined. The ...
DOCTYPE html> var myArray = new Array(4); myArray[0] = "A"; myArray[1] = undefined; myArray[2] = "C"; myArray[3] = "D"; myArray[6] = "E"; delete myArray[2] for (var i = 0; i < myArray.length; i++){ if (myArray[i] != undefined) document.write("myArra...
javascript 数组中删除元素用 array.splice(start, deleteCount);这个方法。 --- deletewill delete the object property, but will not reindex the array or update its length. This makes it appears as if it is undefined: > myArray = ['a','b','c','d'] ["a","b","c","d"] >delete...
Open Compiler const arr = [10, 20, 30, 40, 50, 60]; delete arr[1]; // deleting 2nd element from array document.getElementById("output").innerHTML = arr + "" + arr[1]; It will produce the following result −10,,30,40,50,60 undefined Deleting Predefined...
> delete myArray[0] true > myArray[0] undefined 1. 2. 3. 4. 5. 6. Note that it is not in fact set to the value undefined, rather the property is removed from the array, making itappearundefined. The Chrome dev tools make this distinction clear by printing ...