filter()

Create an Array of elements filtered by a Function.

Signature

filter(predicate: (element: T) => Boolean | Null): Array<T>

Description

The filter() method calls the predicate Function with each Array element as a parameter. The Array elements are passed as a parameter, sequentially, to predicate. The method creates an Array that consists of the Array elements for which the function calls evaluate to true.

The calling Array isn’t changed.

Parameters

Parameter Type Required Description

predicate

Function

Yes

Function to apply to each element of the calling Array. The predicate parameter must reference a boolean Function that evaluate to true or false when applied to the element parameter, or Null.

predicate parameters:

Parameter Type Required Description

element

Any

Array element to evaluate.

Return value

Type Description

Array

New Array that consists of the elements that evaluate to true when the predicate Function is applied to the calling Array. If no predicate calls evaluate to true, the method returns an empty Array.

Examples

Use the arrow Function to filter the Array elements:

[1, 2, 3, 4, 5].filter((x) => {x == 1 || x == 4})
[
  1,
  4
]

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