JavaScript Array Reference
Last Updated :
16 Jan, 2024
JavaScript Array is used to store multiple elements in a single variable. It can hold various data types, including numbers, strings, objects, and even other arrays. It is often used when we want to store a list of elements and access them by a single variable.
Syntax:
const arr = ["Item1", "Item2", "Item3", ...];
Example: Creating an array and copying its items to another array, and displaying the copied items.
JavaScript
let courses = ["HTML", "CSS", "JavaScript", "React"];
console.log(courses);
let newArray = [];
courses.forEach(function (course) {
newArray.push(course);
});
console.log(newArray);
|
Output
[ 'HTML', 'CSS', 'JavaScript', 'React' ]
[ 'HTML', 'CSS', 'JavaScript', 'React' ]
JavaScript Array Constructor
In JavaScript, a constructor gets called when an object is created using the new keyword.
| Array() |
It is used to create an array. |
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JavaScript Array Properties
A JavaScript property is a member of an object that associates a key with a value.
Instance Property:
An instance property is a property that has a new copy for every new instance of the class.
| constructor |
Returns only reference of the function and does not return the name of the function. |
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| length |
Set or return the number of elements in an array. |
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JavaScript Array Methods
JavaScript methods are actions that can be performed on objects.
Static Method:
If the method is called using the array class itself then it is called a static method.
| from() |
Returns an array object from any object with a length property or an iterable object. |
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| isArray() |
Returns true if the argument passed is an array else it returns false. |
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| of() |
Creates a new array instance with variables present as the argument of the function. |
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Instance Method:
If the method is called on an instance of a array then it is called an instance method.
| at() |
Returns the element of that index |
|
| concat() |
Merge two or more arrays together. |
|
| copyWithin() |
Copies part of an array to the same array itself and returns. |
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| entries() |
Fetch all the entries of the same data structure. |
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| every() |
checks that whether all the elements of the array satisfy the given condition. |
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| fill() |
Fill the array with a given static value. |
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| filter() |
Builds a new array containing elements that satisfy a function’s test. |
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| find() |
Get the value of the first element in the array that satisfies the provided condition. |
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| findIndex() |
Return the first index of the element in a given array that satisfies the provided testing function. |
|
| flat() |
Flatten an array, to reduce the nesting of an array. |
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| flatMap() |
This is used to flatten the input array element into a new array. |
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| forEach() |
It is provided a function once for each element of the array. |
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| includes() |
If an array contains the certain value, it returns true. |
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| indexOf() |
Return the first index at which a given element may be found, or -1 if it does not exist. |
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| join() |
Join the elements of an array into a string. |
|
| keys() |
Return a new array iterator which contains the keys for each index in the given input array. |
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| lastIndexOf() |
Return the last index at which a given element may be found, or -1 if it does not exist. |
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| map() |
Calls the argument function once for each element of the given array in order. |
|
| pop() |
Remove the last element of the array and also returns the removed element. |
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| push() |
Push one or more values into the array. |
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| reduce() |
Reduce the array to a single value and executes a provided function for each value of the array. |
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| reduceRight() |
Convert elements of the given array from right to left to a single value. |
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| reverse() |
This is used for the in-place reversal of the array. |
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| shift() |
Removes the first element of the array thus reducing the size of the original array by 1. |
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| slice() |
Returns a new array containing a portion of the array on which it is implemented. |
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| some() |
Each array element’s callback function is run once. |
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| sort() |
Sort an array in place in a given order according to the compare() function. |
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| splice() |
Modify the contents of an array by removing the existing elements. |
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| toLocaleString() |
Convert the elements of the given array to string. |
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| toString() |
Return the string representation of the array elements. |
|
| unshift() |
Add one or more elements to the beginning of the given array. |
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| values() |
Return a new array Iterator object that contains the values for each index in the array. |
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