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• 句法
• 描述
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

concat() method is used to merge two or more arrays. This method does not change the existing arrays, but instead returns a new array.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

句法

const new_array = old_array.concat([value1[, value2[, ...[, valueN]]]])
					

参数

value N 可选

Arrays and/or values to concatenate into a new array. If all value N parameters are omitted, concat returns a shallow copy of the existing array on which it is called. See the description below for more details.

返回值

A new Array 实例。

描述

concat method creates a new array consisting of the elements in the object on which it is called, followed in order by, for each argument, the elements of that argument (if the argument is an array) or the argument itself (if the argument is not an array). It does not recurse into nested array arguments.

concat method does not alter this or any of the arrays provided as arguments but instead returns a shallow copy that contains copies of the same elements combined from the original arrays. Elements of the original arrays are copied into the new array as follows:

• Object references (and not the actual object): concat copies object references into the new array. Both the original and new array refer to the same object. That is, if a referenced object is modified, the changes are visible to both the new and original arrays. This includes elements of array arguments that are also arrays.
• Data types such as strings, numbers and booleans (not String , Number ，和 布尔 objects): concat copies the values of strings and numbers into the new array.

注意： Concatenating array(s)/value(s) will leave the originals untouched. Furthermore, any operation on the new array (except operations on elements which are object references) will have no effect on the original arrays, and vice versa.

范例

Concatenating two arrays

The following code concatenates two arrays:

const letters = ['a', 'b', 'c'];
const numbers = [1, 2, 3];
letters.concat(numbers);
// result in ['a', 'b', 'c', 1, 2, 3]
					

Concatenating three arrays

The following code concatenates three arrays:

const num1 = [1, 2, 3];
const num2 = [4, 5, 6];
const num3 = [7, 8, 9];
const numbers = num1.concat(num2, num3);
console.log(numbers);
// results in [1, 2, 3, 4, 5, 6, 7, 8, 9]
					

Concatenating values to an array

The following code concatenates three values to an array:

const letters = ['a', 'b', 'c'];
const alphaNumeric = letters.concat(1, [2, 3]);
console.log(alphaNumeric);
// results in ['a', 'b', 'c', 1, 2, 3]
					

Concatenating nested arrays

The following code concatenates nested arrays and demonstrates retention of references:

const num1 = [[1]];
const num2 = [2, [3]];
const numbers = num1.concat(num2);
console.log(numbers);
// results in [[1], 2, [3]]
// modify the first element of num1
num1[0].push(4);
console.log(numbers);
// results in [[1, 4], 2, [3]]
					

规范

规范
ECMAScript (ECMA-262) The definition of 'Array.prototype.concat' in that specification.

浏览器兼容性

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
concat	Chrome 1	Edge 12	Firefox 1	IE 5.5	Opera 4	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100

图例

完整支持

完整支持

另请参阅

• push / pop — add/remove elements from the end of the array
• unshift / shift — add/remove elements from the beginning of the array
• splice — add/remove elements from the specified location of the array
• String.prototype.concat()
• Symbol.isConcatSpreadable – control flattening.

元数据

• 最后修改： Mar 4, 2020

相关话题

1. 标准内置对象
2. Array
3. 特性
   1. Array.prototype.length
   2. Array.prototype[@@unscopables]
4. 方法
   1. Array.from()
   2. Array.isArray()
   3. Array.of()
   4. Array.prototype.concat()
   5. Array.prototype.copyWithin()
   6. Array.prototype.entries()
   7. Array.prototype.every()
   8. Array.prototype.fill()
   9. Array.prototype.filter()
   10. Array.prototype.find()
   11. Array.prototype.findIndex()
   12. Array.prototype.flat()
   13. Array.prototype.flatMap()
   14. Array.prototype.forEach()
   15. Array.prototype.includes()
   16. Array.prototype.indexOf()
   17. Array.prototype.join()
   18. Array.prototype.keys()
   19. Array.prototype.lastIndexOf()
   20. Array.prototype.map()
   21. Array.prototype.pop()
   22. Array.prototype.push()
   23. Array.prototype.reduce()
   24. Array.prototype.reduceRight()
   25. Array.prototype.reverse()
   26. Array.prototype.shift()
   27. Array.prototype.slice()
   28. Array.prototype.some()
   29. Array.prototype.sort()
   30. Array.prototype.splice()
   31. Array.prototype.toLocaleString()
   32. Array.prototype.toSource()
   33. Array.prototype.toString()
   34. Array.prototype.unshift()
   35. Array.prototype.values()
   36. Array.prototype[@@iterator]()
   37. get Array[@@species]
5. 继承：
6. Function
7. 特性
   1. Function.arguments
   2. Function.caller
   3. Function.displayName
   4. Function.length
   5. Function.name
8. 方法
   1. Function.prototype.apply()
   2. Function.prototype.bind()
   3. Function.prototype.call()
   4. Function.prototype.toSource()
   5. Function.prototype.toString()
9. Object
10. 特性
    1. Object.prototype.__proto__
    2. Object.prototype.constructor
11. 方法
    1. Object.prototype.__defineGetter__()
    2. Object.prototype.__defineSetter__()
    3. Object.prototype.__lookupGetter__()
    4. Object.prototype.__lookupSetter__()
    5. Object.prototype.hasOwnProperty()
    6. Object.prototype.isPrototypeOf()
    7. Object.prototype.propertyIsEnumerable()
    8. Object.prototype.toLocaleString()
    9. Object.prototype.toSource()
    10. Object.prototype.toString()
    11. Object.prototype.valueOf()
    12. Object.setPrototypeOf()