28 Javascript Array Methods: A Cheat Sheet for Developer

Array.map()

Returns a new array with the results of calling a provided function on every element in this array.

Array.filter()

Returns a new array with all elements that pass the test implemented by the provided function.

Array.reduce()

Reduce the array to a single value. The value returned by the function is stored in an accumulator (result/total).

Array.reduceRight()

Executes a reducer function (that you provide) on each element of the array resulting in a single output value(from right to left).

Array.fill()

Fill the elements in an array with a static value.

Array.find()

Returns the value of the first element in the array that satisfies the provided testing function. Otherwise undefined is returned.

Array.indexOf()

Returns the first index at which a given element can be found in the array, or -1 if it is not present.

Array.lastIndexOf()

Returns the last index at which a given element can be found in the array, or -1 if it is not present. The array is searched backward, starting at fromIndex.

Array.findIndex()

Returns the index of the first element in the array that satisfies the provided testing function. Otherwise, -1 is returned.

Array.includes()

Returns true if the given element is present in the array.

Array.pop()

Removes the last element from an array and returns that element.

Array.push()

Appends new elements to the end of an array, and returns the new length.

Array.shift()

Removes the first element from an array and returns that element.

Array.unshift()

Adds new elements to the beginning of an array, and returns the new length.

Array.splice()

Changes the contents of an array by removing or replacing existing elements and/or adding new elements in place.

Array.slice()

Returns a shallow copy of a portion of an array into a new array object selected from beginning to end (end not included). The original array will not be modified.

Array.join()

Joins all elements of an array into a string.

Array.reverse()

Reverses the order of the elements in an array.

Array.sort()

Sorts the elements of an array in place and returns the array. The default sort order is according to string Unicode code points.

Array.some()

Returns true if at least one element in the array passes the test implemented by the provided function.

Array.every()

Returns true if all elements in the array pass the test implemented by the provided function.

Array.from()

Creates a new array from an array-like or iterable object.

Array.of()

Creates a new array with a variable number of arguments, regardless of the number or type of the arguments.

Array.isArray()

Returns true if the given value is an array.

Array.at()

Returns a value at the specified index.

Array.copyWithin()

Copies array elements within the array. Returns the modified array.

NOTE: 🤔

• the first argument is the target from which to start copying elements.
• the second argument is the index at which to start copying elements.
• the third argument is the index at which to stop copying elements.

Array.flat()

Returns a new array with all sub-array elements concatenated into it recursively up to the specified depth.

Array.flatMap()

Returns a new array formed by applying a given callback function to each element of the array,

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