Use the Array.prototype.push method to append values to the end of an array:
Copy// initialize array
var arr = [
"Hi",
"Hello",
"Bonjour"
];
// append new value to the array
arr.push("Hola");
console.log(arr);
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You can use the push() function to append more than one value to an array in a single call:
Copy// initialize array
var arr = ["Hi", "Hello", "Bonjour", "Hola"];
// append multiple values to the array
arr.push("Salut", "Hey");
// display all values
for (var i = 0; i < arr.length; i++) {
console.log(arr[i]);
}
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Note that the push() method returns the updated length of the array.
Update
If you want to add the items of one array to another array, you can use firstArray.concat(secondArray):
Copyvar arr = [
"apple",
"banana",
"cherry"
];
// Do not forget to assign the result as, unlike push, concat does not change the existing array
arr = arr.concat([
"dragonfruit",
"elderberry",
"fig"
]);
console.log(arr);
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Update
Just an addition to this answer if you want to prepend any value to the start of an array (i.e. first index) then you can use Array.prototype.unshift for this purpose.
Copyvar arr = [1, 2, 3];
arr.unshift(0);
console.log(arr);
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It also supports appending multiple values at once just like push.
Update
Another way with ES6 syntax is to return a new array with the spread syntax. This leaves the original array unchanged, but returns a new array with new items appended or prepended, compliant with the spirit of functional programming.
Copyconst arr1 = [
"Hi",
"Hello",
"Bonjour",
];
const arr2 = [
"Ciao",
"Hej",
"Merhaba",
];
const newArr1 = [
...arr1,
"Salut",
];
const newArr2 = [
"Salut",
...arr2,
];
const newArr3 = [
...arr1,
...arr2,
];
console.log(newArr1, newArr2, newArr3);
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Videos
Use the Array.prototype.push method to append values to the end of an array:
Copy// initialize array
var arr = [
"Hi",
"Hello",
"Bonjour"
];
// append new value to the array
arr.push("Hola");
console.log(arr);
Run code snippetEdit code snippet Hide Results Copy to answer Expand
You can use the push() function to append more than one value to an array in a single call:
Copy// initialize array
var arr = ["Hi", "Hello", "Bonjour", "Hola"];
// append multiple values to the array
arr.push("Salut", "Hey");
// display all values
for (var i = 0; i < arr.length; i++) {
console.log(arr[i]);
}
Run code snippetEdit code snippet Hide Results Copy to answer Expand
Note that the push() method returns the updated length of the array.
Update
If you want to add the items of one array to another array, you can use firstArray.concat(secondArray):
Copyvar arr = [
"apple",
"banana",
"cherry"
];
// Do not forget to assign the result as, unlike push, concat does not change the existing array
arr = arr.concat([
"dragonfruit",
"elderberry",
"fig"
]);
console.log(arr);
Run code snippetEdit code snippet Hide Results Copy to answer Expand
Update
Just an addition to this answer if you want to prepend any value to the start of an array (i.e. first index) then you can use Array.prototype.unshift for this purpose.
Copyvar arr = [1, 2, 3];
arr.unshift(0);
console.log(arr);
Run code snippetEdit code snippet Hide Results Copy to answer Expand
It also supports appending multiple values at once just like push.
Update
Another way with ES6 syntax is to return a new array with the spread syntax. This leaves the original array unchanged, but returns a new array with new items appended or prepended, compliant with the spirit of functional programming.
Copyconst arr1 = [
"Hi",
"Hello",
"Bonjour",
];
const arr2 = [
"Ciao",
"Hej",
"Merhaba",
];
const newArr1 = [
...arr1,
"Salut",
];
const newArr2 = [
"Salut",
...arr2,
];
const newArr3 = [
...arr1,
...arr2,
];
console.log(newArr1, newArr2, newArr3);
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If you're only appending a single variable, then push() works just fine. If you need to append another array, use concat():
Copyvar ar1 = [1, 2, 3];
var ar2 = [4, 5, 6];
var ar3 = ar1.concat(ar2);
alert(ar1);
alert(ar2);
alert(ar3);
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The concat does not affect ar1 and ar2 unless reassigned, for example:
Copyvar ar1 = [1, 2, 3];
var ar2 = [4, 5, 6];
ar1 = ar1.concat(ar2);
alert(ar1);
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There is a lot of great information on JavaScript Reference.
Use the concat function, like so:
var arrayA = [1, 2];
var arrayB = [3, 4];
var newArray = arrayA.concat(arrayB);
The value of newArray will be [1, 2, 3, 4] (arrayA and arrayB remain unchanged; concat creates and returns a new array for the result).
In ECMAScript 6, you can use the Spread syntax:
let arr1 = [0, 1, 2];
let arr2 = [3, 4, 5];
arr1.push(...arr2);
console.log(arr1)Spread syntax is available in all major browsers (that excludes IE11). For the current compatibility, see this (continuously updated) compatibility table.
However, see Jack Giffin's reply below for more comments on performance. It seems concat is still better and faster than the spread operator.