array.filter()

Filter an Array using a provided predicate.

Signature

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

Description

Returns an Array containing elements of the calling Array that match a provided predicate function.

The calling Array isn’t changed.

Parameters

Parameter Type Required Description

predicate

Predicate function

true

Anonymous predicate function that:

  • Accepts an Array element as its only argument. You can pass in this argument using arrow function syntax.

  • Returns Boolean or Null.

If the predicate evaluates to true for an element, the element is included in the Array returned by the method.

Return value

Type Description

Array<Generic>

Array containing elements that evaluate to true for the provided predicate.

If no elements evaluate to true, the method returns an empty Array.

Examples

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

See also

array.where()

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