array.firstWhere()

This method operates on an array. You typically fetch documents from a collection as a set, not an Array. For the equivalent Set method, see set instance methods.

For differences between Sets and Arrays, see Sets vs. Arrays.

Get the first Array value that matches the given predicate.

Signature

firstWhere(predicate: () => Boolean | Null) => T | Null

firstWhere(predicate: (val: T) => Boolean | Null) => T | Null

Description

The firstWhere() method gets the first matching Array value that matches predicate.

Parameters

Parameter Type Required Description

predicate

Function

Yes

Anonymous Function that compares a Array value and returns true for matches, false for mismatches, or Null.

predicate parameters:

Parameter Type Required Description

val

Any

The Array value to compare. If omitted, use dot notation to access value properties.

Return value

Type Description

Any

First matching value in the Array or null if the Array is empty or no values match.

Examples

let iter = [1, 2, 3, 4]
iter.firstWhere(v => v > 2)
3

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