JavaScript Array Methods

📄️ concat()

concat() populates a new array with the concatenation of its calling array and its arguments.

every() returns true if all its calling array's items pass its function argument's test. Otherwise, it returns false.

filter() creates a new array that contains all the calling array's elements that passed the test specified by the method's argument.

find() finds the calling array's element that first passes the test specified by the method's function argument.

findIndex() finds the index of the calling array's element that first passes the test specified by the method's function argument.

The forEach() method invokes its argument once for each item of an existing array.

includes() checks if its calling array includes the method's first argument.

indexOf() searches its calling array for the first occurrence of the method's string argument.

join() creates a new string by using a comma, or a user-defined separator, to join the elements of an array object.

lastIndexOf() searches its calling array for the last occurrence of the method's argument.

map() creates a new array that contains the result of invoking map()'s function argument on each item of the calling array.

JavaScript's pop() method removes and returns its calling array's last item. It does not accept any argument.

JavaScript's push() method adds its arguments to the end of its calling array and returns the calling array's new length.

Whenever you use reduce() on an array, the method uses its function argument to reduce its calling array's items to a single value.

reverse() reverses an array so that its first item becomes the last and its last element becomes the first.

JavaScript's shift() method removes and returns its calling array's first item. It does not accept any argument.

JavaScript's slice() method duplicates a specified part of its calling array into a new array—without altering the original array.

some() returns true if some of its calling array's items pass its function argument's test. Otherwise, it returns false.

sort() sorts its calling array's items in ascending (or descending) order and returns the sorted array.

JavaScript's splice() method alters its calling array by adding or removing a specific number of items to/from it.

JavaScript's unshift() method adds its arguments to the beginning of its calling array and returns the calling array's new length.