The JavaScript method toString() converts an array to a string of (comma separated) array values.
var fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo").innerHTML = fruits.toString();
Banana,Orange,Apple,Mango
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The join() method also joins all array elements into a string.
It behaves just like toString(), but in addition you can specify the separator:
var fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo").innerHTML = fruits.join(" * ");
Banana * Orange * Apple * Mango
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When you work with arrays, it is easy to remove elements and add new elements.
This is what popping and pushing is:
Popping items out of an array, or pushing items into an array.
The pop() method removes the last element from an array:
var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.pop();
// Removes the last element ("Mango") from fruits
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The pop() method returns the value that was "popped out":
var fruits = ["Banana", "Orange", "Apple", "Mango"];
var x =
fruits.pop();
// the value of x is "Mango"
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The push() method adds a new element to an array (at the end):
var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.push("Kiwi"); // Adds a new element ("Kiwi") to fruits
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The push() method returns the new array length:
var fruits = ["Banana", "Orange", "Apple", "Mango"];
var x =
fruits.push("Kiwi"); // the value of x is 5
Try it Yourself »Shifting is equivalent to popping, working on the first element instead of the last.
The shift() method removes the first array element and "shifts" all other elements to a lower index.
var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.shift();
// Removes the first element "Banana" from fruits
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The shift() method returns the string that was "shifted out":
var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.shift(); //
Returns "Banana"
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The unshift() method adds a new element to an array (at the beginning), and "unshifts" older elements:
var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.unshift("Lemon");
// Adds a new element "Lemon" to fruits
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The unshift() method returns the new array length.
var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.unshift("Lemon");
// Returns 5
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Array elements are accessed using their index number:
Array indexes start with 0. [0] is the first array element, [1] is the second, [2] is the third ...
var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits[0] = "Kiwi";
// Changes the first element of fruits to "Kiwi"
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The length property provides an easy way to append a new element to an array:
var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits[fruits.length] = "Kiwi";
// Appends "Kiwi" to fruit
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Since JavaScript arrays are objects, elements can be deleted by using the JavaScript operator delete:
var fruits = ["Banana", "Orange", "Apple", "Mango"];
delete fruits[0];
// Changes the first element in fruits to undefined
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Using delete may leave undefined holes in the array. Use pop() or shift() instead.
The splice() method can be used to add new items to an array:
array.splice(index, howmany, item1, ....., itemX)
var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.splice(2, 0, "Lemon", "Kiwi");
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The first parameter (2) defines the position where new elements should be added (spliced in).
The second parameter (0) defines how many elements should be removed.
The rest of the parameters ("Lemon" , "Kiwi") define the new elements to be added.
With clever parameter setting, you can use splice() to remove elements without leaving "holes" in the array:
var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.splice(0, 1);
// Removes the first element of fruits
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The first parameter (0) defines the position where new elements should be added (spliced in).
The second parameter (1) defines how many elements should be removed.
The rest of the parameters are omitted. No new elements will be added.
The concat() method creates a new array by merging (concatenating) existing arrays:
var myGirls = ["Cecilie", "Lone"];
var myBoys = ["Emil", "Tobias", "Linus"];
var myChildren = myGirls.concat(myBoys);
// Concatenates (joins) myGirls and myBoys
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The concat() method does not change the existing arrays. It always returns a new array.
The concat() method can take any number of array arguments:
var arr1 = ["Cecilie", "Lone"];
var arr2 = ["Emil", "Tobias", "Linus"];
var arr3 = ["Robin", "Morgan"];
var myChildren = arr1.concat(arr2, arr3);
// Concatenates arr1 with arr2 and arr3
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The concat() method can also take values as arguments:
var arr1 = ["Cecilie", "Lone"];
var myChildren = arr1.concat(["Emil", "Tobias", "Linus"]);
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The slice() method slices out a piece of an array into a new array.
This example slices out a part of an array starting from array element 1 ("Orange"):
var fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];
var citrus = fruits.slice(1);
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The slice() method creates a new array. It does not remove any elements from the source array.
This example slices out a part of an array starting from array element 3 ("Apple"):
var fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];
var citrus = fruits.slice(3);
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The slice() method can take two arguments like slice(1, 3).
The method then selects elements from the start argument, and up to (but not including) the end argument.
var fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];
var citrus = fruits.slice(1, 3);
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If the end argument is omitted, like in the first examples, the slice() method slices out the rest of the array.
var fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];
var citrus = fruits.slice(2);
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JavaScript automatically converts an array to a comma separated string when a primitive value is expected.
This is always the case when you try to output an array.
These two examples will produce the same result:
var fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo").innerHTML = fruits.toString();
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var fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo").innerHTML = fruits;
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All JavaScript objects have a toString() method.
There are no built-in functions for finding the highest or lowest value in a JavaScript array.
You will learn how you solve this problem in the next chapter of this tutorial.
Sorting arrays are covered in the next chapter of this tutorial.
For a complete reference, go to our Complete JavaScript Array Reference.
The reference contains descriptions and examples of all Array properties and methods.
The Array object is used to store multiple values in a single variable:
var cars = ["Saab", "Volvo", "BMW"];
Array indexes are zero-based: The first element in the array is 0, the second is 1, and so on.
For a tutorial about Arrays, read our JavaScript Array Tutorial.
| Property | Description |
|---|---|
| constructor | Returns the function that created the Array object's prototype |
| length | Sets or returns the number of elements in an array |
| prototype | Allows you to add properties and methods to an Array object |
| Method | Description |
|---|---|
| concat() | Joins two or more arrays, and returns a copy of the joined arrays |
| copyWithin() | Copies array elements within the array, to and from specified positions |
| entries() | Returns a key/value pair Array Iteration Object |
| every() | Checks if every element in an array pass a test |
| fill() | Fill the elements in an array with a static value |
| filter() | Creates a new array with every element in an array that pass a test |
| find() | Returns the value of the first element in an array that pass a test |
| findIndex() | Returns the index of the first element in an array that pass a test |
| forEach() | Calls a function for each array element |
| from() | Creates an array from an object |
| includes() | Check if an array contains the specified element |
| indexOf() | Search the array for an element and returns its position |
| isArray() | Checks whether an object is an array |
| join() | Joins all elements of an array into a string |
| keys() | Returns a Array Iteration Object, containing the keys of the original array |
| lastIndexOf() | Search the array for an element, starting at the end, and returns its position |
| map() | Creates a new array with the result of calling a function for each array element |
| pop() | Removes the last element of an array, and returns that element |
| push() | Adds new elements to the end of an array, and returns the new length |
| reduce() | Reduce the values of an array to a single value (going left-to-right) |
| reduceRight() | Reduce the values of an array to a single value (going right-to-left) |
| reverse() | Reverses the order of the elements in an array |
| shift() | Removes the first element of an array, and returns that element |
| slice() | Selects a part of an array, and returns the new array |
| some() | Checks if any of the elements in an array pass a test |
| sort() | Sorts the elements of an array |
| splice() | Adds/Removes elements from an array |
| toString() | Converts an array to a string, and returns the result |
| unshift() | Adds new elements to the beginning of an array, and returns the new length |
| valueOf() | Returns the primitive value of an array |