Concatenating Arrays‌ JavaScript

Concatenating Arrays‌ JavaScript
Two Arrays var array1 = [1, 2]; var array2 = [3, 4, 5]; Version ≥ 3 var array3 = array1.concat(array2); // returns a new array Version ≥ 6 var array3 = [...array1, ...array2] Results in a new Array: [1, 2, 3, 4, 5] Multiple Arrays var array1 = ["a", "b"], array2 = ["c", "d"], array3 = ["e", "f"], array4 = ["g", "h"]; Provide more Array arguments to array.concat() var arrConc = array1.concat(array2, array3, array4); Version ≥ 6 Provide more arguments to [] var arrConc = [...array1, ...array2, ...array3, ...array4] Results in a new Array: ["a", "b", "c", "d", "e", "f", "g", "h"] Without Copying the First Array var longArray = [1, 2, 3, 4, 5, 6, 7, 8], shortArray = [9, 10]; Version ≥ 3 Provide the elements of shortArray as parameters to push using Function.prototype.apply longArray.push.apply(longArray, shortArray); Version ≥ 6 Use the spread operator to pass the elements of shortArray as separate arguments to push longArray.push(...shortArray) The value of longArray is now: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] Note that if the second array is too long (>100,000 entries), you may get a stack overflow error (because of how apply works). To be safe, you can iterate instead: shortArray.forEach(function (elem) { longArray.push(elem); }); Array and non-array values var array = ["a", "b"]; Version ≥ 3 var arrConc = array.concat("c", "d"); Version ≥ 6 var arrConc = [...array, "c", "d"] Results in a new Array: ["a", "b", "c", "d"] You can also mix arrays with non-arrays var arr1 = ["a","b"]; var arr2 = ["e", "f"]; var arrConc = arr1.concat("c", "d", arr2); Results in a new Array: ["a", "b", "c", "d", "e", "f"] Noted that: Above full tutorial makes good

Concatenating Arrays‌ JavaScript

Two Arrays

var array1 = [1, 2];
var array2 = [3, 4, 5];
Version ≥ 3
var array3 = array1.concat(array2); // returns a new array
Version ≥ 6
var array3 = [...array1, ...array2]

Results in a new Array:

[1, 2, 3, 4, 5]

Multiple Arrays

var array1 = ["a", "b"],
array2 = ["c", "d"],
array3 = ["e", "f"],
array4 = ["g", "h"];

Provide more Array arguments to array.concat()

var arrConc = array1.concat(array2, array3, array4);
Version ≥ 6

Provide more arguments to []

var arrConc = [...array1, ...array2, ...array3, ...array4]

Results in a new Array:

["a", "b", "c", "d", "e", "f", "g", "h"]

Without Copying the First Array

var longArray = [1, 2, 3, 4, 5, 6, 7, 8],
shortArray = [9, 10];
Version ≥ 3

Provide the elements of shortArray as parameters to push using Function.prototype.apply

longArray.push.apply(longArray, shortArray);
Version ≥ 6

Use the spread operator to pass the elements of shortArray as separate arguments to push

longArray.push(...shortArray)

The value of longArray is now:

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Note that if the second array is too long (>100,000 entries), you may get a stack overflow error (because of how

apply works). To be safe, you can iterate instead:

shortArray.forEach(function (elem) { longArray.push(elem);
});

Array and non-array values

var array = ["a", "b"];
Version ≥ 3
var arrConc = array.concat("c", "d");
Version ≥ 6
var arrConc = [...array, "c", "d"]

Results in a new Array:

["a", "b", "c", "d"]

You can also mix arrays with non-arrays

var arr1 = ["a","b"];
var arr2 = ["e", "f"];
var arrConc = arr1.concat("c", "d", arr2);

Results in a new Array:

["a", "b", "c", "d", "e", "f"]

Noted that: Above full tutorial makes good

Published:	December 31, 2022
Author:	admin
Category:	Javascript Source Code
Views:	22

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