API / JavaScript / Belt / MutableQueue


An FIFO(first in first out) queue data structure.

type t('a);

The type of queues containing elements of type('a).

let make: unit => t('a);

Returns a new queue, initially empty.

let clear: t('a) => unit;

Discard all elements from the queue.

let isEmpty: t('a) => bool;

Returns true if the given queue is empty, false otherwise.

let fromArray: array('a) => t('a);

fromArray a is equivalent to Array.forEach(a, add(q, a));

let add: (t('a), 'a) => unit;

add(q, x) adds the element x at the end of the queue q.

let peek: t('a) => option('a);

peekOpt(q) returns the first element in queue q, without removing it from the queue.

let peekUndefined: t('a) => Js.undefined('a);

peekUndefined(q) returns undefined if not found.

let peekExn: t('a) => 'a;

raise an exception if q is empty

let pop: t('a) => option('a);

pop(q) removes and returns the first element in queue q.

let popUndefined: t('a) => Js.undefined('a);

popUndefined(q) removes and returns the first element in queue q. it will return undefined if it is already empty.

let popExn: t('a) => 'a;

popExn(q) raise an exception if q is empty.

let copy: t('a) => t('a);

copy(q) returns a fresh queue.

let size: t('a) => int;

Returns the number of elements in a queue.

let mapU: (t('a), [@bs] ('a => 'b)) => t('b);
let map: (t('a), 'a => 'b) => t('b);
let forEachU: (t('a), [@bs] ('a => unit)) => unit;
let forEach: (t('a), 'a => unit) => unit;

forEach(q, f) appliesfin turn to all elements ofq`, from the least recently entered to the most recently entered. The queue itself is unchanged.

let reduceU: (t('a), 'b, [@bs] (('b, 'a) => 'b)) => 'b;
let reduce: (t('a), 'b, ('b, 'a) => 'b) => 'b;

reduce(q, accu, f) is equivalent to List.reduce(l, accu, f), where l is the list of q's elements. The queue remains unchanged.

let transfer: (t('a), t('a)) => unit;

transfer(q1, q2) adds all of q1's elements at the end of the queue q2, then clears q1. It is equivalent to the sequence forEach((x) => add(x, q2), q1);; clear q1, but runs in constant time.

let toArray: t('a) => array('a);

First added will be in the beginning of the array.