Question

Checks whether the given value is in this sequence.

Signature

Sequence.contains = function(value, equalityFn) { /*...*/ }

Sequence.contains = function contains(value, equalityFn) {
  return this.indexOf(value, equalityFn) !== -1;
}

Name	Type(s)	Description
value	*	The element to search for in the sequence.
equalityFn	Function?	An optional equality function, which should take two arguments and return true or false to indicate whether those values are considered equal.
returns	boolean	True if the sequence contains the value, false if not.

Examples

var numbers = [5, 10, 15, 20];

Lazy(numbers).contains(15) // => true
Lazy(numbers).contains(13) // => false