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JavaScript Array Reference

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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




// Create and initialize an array
let courses = ["HTML", "CSS", "JavaScript", "React"];
  
// Display the array items
console.log(courses);
   
// Create a new empty array
let newArray = [];
   
// forEach loop to push elements
// into new array
courses.forEach(function (course) {
    newArray.push(course);
});
   
// Display the new array of items
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.

Constructor

Descriptions

Examples

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.

Instance Properties

Descriptions

Examples

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.

Static Methods

Descriptions

Examples

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.

Instance Methods

Descriptions

Examples

at() Returns the element of that index
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concat() Merge two or more arrays together.
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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.
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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.
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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.
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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.
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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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Last Updated : 16 Jan, 2024
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