| # yocto-queue [](https://bundlephobia.com/result?p=yocto-queue) |
|
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| > Tiny queue data structure |
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| You should use this package instead of an array if you do a lot of `Array#push()` and `Array#shift()` on large arrays, since `Array#shift()` has [linear time complexity](https://medium.com/@ariel.salem1989/an-easy-to-use-guide-to-big-o-time-complexity-5dcf4be8a444#:~:text=O(N)%E2%80%94Linear%20Time) *O(n)* while `Queue#dequeue()` has [constant time complexity](https://medium.com/@ariel.salem1989/an-easy-to-use-guide-to-big-o-time-complexity-5dcf4be8a444#:~:text=O(1)%20%E2%80%94%20Constant%20Time) *O(1)*. That makes a huge difference for large arrays. |
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| > A [queue](https://en.wikipedia.org/wiki/Queue_(abstract_data_type)) is an ordered list of elements where an element is inserted at the end of the queue and is removed from the front of the queue. A queue works based on the first-in, first-out ([FIFO](https://en.wikipedia.org/wiki/FIFO_(computing_and_electronics))) principle. |
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| ## Install |
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| ```sh |
| npm install yocto-queue |
| ``` |
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| ## Usage |
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| ```js |
| import Queue from 'yocto-queue'; |
| |
| const queue = new Queue(); |
| |
| queue.enqueue('🦄'); |
| queue.enqueue('🌈'); |
| |
| console.log(queue.size); |
| //=> 2 |
| |
| console.log(...queue); |
| //=> '🦄 🌈' |
| |
| console.log(queue.dequeue()); |
| //=> '🦄' |
| |
| console.log(queue.dequeue()); |
| //=> '🌈' |
| ``` |
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| ## API |
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| ### `queue = new Queue()` |
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| The instance is an [`Iterable`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols), which means you can iterate over the queue front to back with a “for…of” loop. Using the iterator will not remove the items from the queue. If you want that, use [`drain()`](#drain) instead. |
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| You can also use spreading to convert the queue to an array. Don't do this unless you really need to though, since it's slow. |
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| #### `.enqueue(value)` |
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| Add a value to the queue. |
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| #### `.dequeue()` |
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| Remove the next value in the queue. |
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| Returns the removed value or `undefined` if the queue is empty. |
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| #### `.peek()` |
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| Get the next value in the queue without removing it. |
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| Returns the value or `undefined` if the queue is empty. |
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| #### `.drain()` |
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| Returns an iterator that dequeues items as you consume it. |
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| This allows you to empty the queue while processing its items. |
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| If you want to not remove items as you consume it, use the `Queue` object as an iterator. |
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| #### `.clear()` |
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| Clear the queue. |
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| #### `.size` |
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| The size of the queue. |
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| ## Related |
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| - [quick-lru](https://github.com/sindresorhus/quick-lru) - Simple “Least Recently Used” (LRU) cache |
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