@kingjs/linq.last-or-undefined

Returns the last element of a sequence that satisfies a specified condition or a undefined.

Usage

Return the last value of 0, 1, 2 like this;

var lastOrUndefined = require('@kingjs/linq.last-or-undefined');
var sequence = require('@kingjs/enumerable.create');

lastOrUndefined.call(sequence(0, 1, 2));

result:

2

Return the last odd value of 0, 1, 2, 3, 4 like this;

var lastOrUndefined = require('@kingjs/linq.last-or-undefined');
var sequence = require('@kingjs/enumerable.create');

var isOdd = function(x) { return x % 2 == 1; }

lastOrUndefined.call(sequence(0, 1, 2, 3, 4), isOdd);

result:

3

API

declare function lastOrUndefined(
  this: Enumerable,
  predicate?: (x) => boolean
)

Interfaces

• Enumerable: See @kingjs/enumerable.define.

Parameters

• this: The sequence of which last element is returned.
• predicate: Optional predicate element must satisfy.

Return Value

Last element in the sequence or undefined if sequence is empty. If a predicate is provided, then the last element to match the predicate else undefined if no element satisfies the predicate.

Install

With npm installed, run

$ npm install @kingjs/linq.last-or-undefined

Acknowledgments

Like Enumerable.LastOrDefault.

License

MIT