The type of the keys in the collection.
The type of the values in the collection.
Returns the value of the first element in the collection that satisfies the provided testing function.
The value of the first element that passes the test. undefined if no element passes the test.
Creates a new array with the results of calling a provided function on every element in the collection.
A new array with the results of calling the provided function on every element in the collection.
Apply a function against an accumulator and each element in the collection (from left to right) to reduce it to a single value.
The value that results from the reduction.
Represents a collection that extends the built-in Map class.