{"id":23349997,"url":"https://github.com/stdlib-js/utils-fifo","last_synced_at":"2026-04-16T17:41:09.985Z","repository":{"id":41359099,"uuid":"376896331","full_name":"stdlib-js/utils-fifo","owner":"stdlib-js","description":"First-in-first-out (FIFO) queue.","archived":false,"fork":false,"pushed_at":"2025-01-20T01:30:29.000Z","size":510,"stargazers_count":1,"open_issues_count":0,"forks_count":0,"subscribers_count":3,"default_branch":"main","last_synced_at":"2025-07-12T22:36:28.290Z","etag":null,"topics":["collection","data","data-structure","data-structures","fifo","first-in","first-out","javascript","node","node-js","nodejs","queue","stdlib","structure","util","utilities","utility","utils"],"latest_commit_sha":null,"homepage":"https://github.com/stdlib-js/stdlib","language":"JavaScript","has_issues":false,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"apache-2.0","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/stdlib-js.png","metadata":{"files":{"readme":"README.md","changelog":"CHANGELOG.md","contributing":"CONTRIBUTING.md","funding":null,"license":"LICENSE","code_of_conduct":"CODE_OF_CONDUCT.md","threat_model":null,"audit":null,"citation":"CITATION.cff","codeowners":null,"security":"SECURITY.md","support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null,"zenodo":null},"funding":{"github":["stdlib-js"],"open_collective":"stdlib","tidelift":"npm/@stdlib/stdlib"}},"created_at":"2021-06-14T16:57:11.000Z","updated_at":"2025-01-20T01:25:41.000Z","dependencies_parsed_at":"2023-02-17T06:25:27.103Z","dependency_job_id":"866403d5-aed2-4f73-b404-ffa03b5c7180","html_url":"https://github.com/stdlib-js/utils-fifo","commit_stats":null,"previous_names":[],"tags_count":27,"template":false,"template_full_name":null,"purl":"pkg:github/stdlib-js/utils-fifo","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Futils-fifo","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Futils-fifo/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Futils-fifo/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Futils-fifo/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/stdlib-js","download_url":"https://codeload.github.com/stdlib-js/utils-fifo/tar.gz/refs/heads/main","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Futils-fifo/sbom","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":269809489,"owners_count":24478548,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2022-07-04T15:15:14.044Z","status":"online","status_checked_at":"2025-08-10T02:00:08.965Z","response_time":71,"last_error":null,"robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":true,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["collection","data","data-structure","data-structures","fifo","first-in","first-out","javascript","node","node-js","nodejs","queue","stdlib","structure","util","utilities","utility","utils"],"created_at":"2024-12-21T08:14:31.237Z","updated_at":"2026-04-16T17:41:04.960Z","avatar_url":"https://github.com/stdlib-js.png","language":"JavaScript","funding_links":["https://github.com/sponsors/stdlib-js","https://opencollective.com/stdlib","https://tidelift.com/funding/github/npm/@stdlib/stdlib"],"categories":[],"sub_categories":[],"readme":"\u003c!--\n\n@license Apache-2.0\n\nCopyright (c) 2018 The Stdlib Authors.\n\nLicensed under the Apache License, Version 2.0 (the \"License\");\nyou may not use this file except in compliance with the License.\nYou may obtain a copy of the License at\n\n   http://www.apache.org/licenses/LICENSE-2.0\n\nUnless required by applicable law or agreed to in writing, software\ndistributed under the License is distributed on an \"AS IS\" BASIS,\nWITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\nSee the License for the specific language governing permissions and\nlimitations under the License.\n\n--\u003e\n\n\n\u003cdetails\u003e\n  \u003csummary\u003e\n    About stdlib...\n  \u003c/summary\u003e\n  \u003cp\u003eWe believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.\u003c/p\u003e\n  \u003cp\u003eThe library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.\u003c/p\u003e\n  \u003cp\u003eWhen you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.\u003c/p\u003e\n  \u003cp\u003eTo join us in bringing numerical computing to the web, get started by checking us out on \u003ca href=\"https://github.com/stdlib-js/stdlib\"\u003eGitHub\u003c/a\u003e, and please consider \u003ca href=\"https://opencollective.com/stdlib\"\u003efinancially supporting stdlib\u003c/a\u003e. We greatly appreciate your continued support!\u003c/p\u003e\n\u003c/details\u003e\n\n# FIFO\n\n[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] \u003c!-- [![dependencies][dependencies-image]][dependencies-url] --\u003e\n\n\u003e First-in-first-out (FIFO) queue.\n\n\u003c!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. --\u003e\n\n\u003csection class=\"intro\"\u003e\n\n\u003c/section\u003e\n\n\u003c!-- /.intro --\u003e\n\n\u003c!-- Package usage documentation. --\u003e\n\n\u003csection class=\"installation\"\u003e\n\n## Installation\n\n```bash\nnpm install @stdlib/utils-fifo\n```\n\nAlternatively,\n\n-   To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).\n-   If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).\n-   For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).\n\nThe [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.\n\nTo view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.\n\n\u003c/section\u003e\n\n\u003csection class=\"usage\"\u003e\n\n## Usage\n\n```javascript\nvar fifo = require( '@stdlib/utils-fifo' );\n```\n\n#### fifo()\n\nReturns a new first-in-first-out (FIFO) queue instance.\n\n```javascript\nvar queue = fifo();\n// returns \u003cFIFO\u003e\n```\n\n##### queue.clear()\n\nClears a queue.\n\n```javascript\nvar queue = fifo();\n// returns \u003cFIFO\u003e\n\n// Add values to the queue:\nqueue.push( 'foo' ).push( 'bar' );\n\n// Peek at the first value:\nvar v = queue.first();\n// returns 'foo'\n\n// Examine the queue length:\nvar len = queue.length;\n// returns 2\n\n// Clear all queue items:\nqueue.clear();\n\n// Peek at the first value:\nv = queue.first();\n// returns undefined\n\n// Examine the queue length:\nlen = queue.length;\n// returns 0\n```\n\n##### queue.first()\n\nReturns the \"oldest\" queue value (i.e., the value which is \"first-out\"). If the queue is currently empty, the returned value is `undefined`.\n\n```javascript\nvar queue = fifo();\n// returns \u003cFIFO\u003e\n\n// Add values to the queue:\nqueue.push( 'foo' ).push( 'bar' );\n\n// Peek at the first value:\nvar v = queue.first();\n// returns 'foo'\n```\n\n##### queue.iterator()\n\nReturns an iterator for iterating over a queue. If an environment supports `Symbol.iterator`, the returned iterator is iterable.\n\n```javascript\nvar queue = fifo();\n\n// Add values to the queue:\nqueue.push( 'foo' ).push( 'bar' );\n\n// Create an iterator:\nvar it = queue.iterator();\n\n// Iterate over the queue...\nvar v = it.next().value;\n// returns 'foo'\n\nv = it.next().value;\n// returns 'bar'\n\nvar bool = it.next().done;\n// returns true\n```\n\n**Note**: in order to prevent confusion arising from queue mutation during iteration, a returned iterator **always** iterates over a queue \"snapshot\", which is defined as the list of queue elements at the time of `queue.iterator()` invocation.\n\n##### queue.last()\n\nReturns the \"newest\" queue value (i.e., the value which is \"last-out\"). If the queue is currently empty, the returned value is `undefined`.\n\n```javascript\nvar queue = fifo();\n// returns \u003cFIFO\u003e\n\n// Add values to the queue:\nqueue.push( 'foo' ).push( 'bar' );\n\n// Peek at the last value:\nvar v = queue.last();\n// returns 'bar'\n```\n\n##### queue.length\n\nQueue length.\n\n```javascript\nvar queue = fifo();\n\n// Examine the initial queue length:\nvar len = queue.length;\n// returns 0\n\n// Add values to the queue:\nqueue.push( 'foo' ).push( 'bar' );\n\n// Retrieve the current queue length:\nlen = queue.length;\n// returns 2\n```\n\n##### queue.pop()\n\nRemoves a value from the queue. If the queue is currently empty, the returned value is `undefined`.\n\n```javascript\nvar queue = fifo();\n\n// Add values to the queue:\nqueue.push( 'foo' ).push( 'bar' );\n\n// Remove the first value:\nvar v = queue.pop();\n// returns 'foo'\n\n// Add a new value to the queue:\nqueue.push( 'beep' );\n\n// Remove the \"oldest\" queue value:\nv = queue.pop();\n// returns 'bar'\n```\n\n##### queue.push( value )\n\nAdds a value to the queue.\n\n```javascript\nvar queue = fifo();\n\n// Add values to the queue:\nqueue.push( 'foo' ).push( 'bar' );\n\n// Remove the first value:\nvar v = queue.pop();\n// returns 'foo'\n\n// Add a new value to the queue:\nqueue.push( 'beep' );\n\n// Remove the \"oldest\" queue value:\nv = queue.pop();\n// returns 'bar'\n```\n\n##### queue.toArray()\n\nReturns an array of queue values.\n\n```javascript\nvar queue = fifo();\n\n// Add values to the queue:\nqueue.push( 'foo' ).push( 'bar' );\n\n// Get an array of queue values:\nvar vals = queue.toArray();\n// returns [ 'foo', 'bar' ]\n```\n\n##### queue.toJSON()\n\nSerializes a queue as JSON.\n\n```javascript\nvar queue = fifo();\n\n// Add values to the queue:\nqueue.push( 'foo' ).push( 'bar' );\n\n// Serialize to JSON:\nvar o = queue.toJSON();\n// returns { 'type': 'fifo', 'data': [ 'foo', 'bar' ] }\n```\n\n**Note**: `JSON.stringify()` implicitly calls this method when stringifying a queue instance.\n\n\u003c/section\u003e\n\n\u003c!-- /.usage --\u003e\n\n\u003c!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. --\u003e\n\n\u003csection class=\"notes\"\u003e\n\n\u003c/section\u003e\n\n\u003c!-- /.notes --\u003e\n\n\u003c!-- Package usage examples. --\u003e\n\n\u003csection class=\"examples\"\u003e\n\n## Examples\n\n\u003c!-- eslint no-undef: \"error\" --\u003e\n\n```javascript\nvar fifo = require( '@stdlib/utils-fifo' );\n\nvar queue;\nvar iter;\nvar len;\nvar v;\nvar i;\n\n// Create a new FIFO queue:\nqueue = fifo();\n\n// Add some values to the queue:\nqueue.push( 'foo' );\nqueue.push( 'bar' );\nqueue.push( 'beep' );\nqueue.push( 'boop' );\n\n// Peek at the first and last queue values:\nv = queue.first();\n// returns 'foo'\n\nv = queue.last();\n// returns 'boop'\n\n// Inspect the queue length:\nlen = queue.length;\n// returns 4\n\n// Remove the \"oldest\" queue value:\nv = queue.pop();\n// returns 'foo'\n\n// Inspect the queue length:\nlen = queue.length;\n// returns 3\n\n// Iterate over the queue:\niter = queue.iterator();\nfor ( i = 0; i \u003c len; i++ ) {\n    console.log( 'Queue value #%d: %s', i+1, iter.next().value );\n}\n\n// Clear the queue:\nqueue.clear();\n\n// Inspect the queue length:\nlen = queue.length;\n// returns 0\n```\n\n\u003c/section\u003e\n\n\u003c!-- /.examples --\u003e\n\n\u003c!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. --\u003e\n\n\u003csection class=\"references\"\u003e\n\n\u003c/section\u003e\n\n\u003c!-- /.references --\u003e\n\n\u003c!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. --\u003e\n\n\u003csection class=\"related\"\u003e\n\n* * *\n\n## See Also\n\n-   \u003cspan class=\"package-name\"\u003e[`@stdlib/utils-stack`][@stdlib/utils/stack]\u003c/span\u003e\u003cspan class=\"delimiter\"\u003e: \u003c/span\u003e\u003cspan class=\"description\"\u003estack.\u003c/span\u003e\n\n\u003c/section\u003e\n\n\u003c!-- /.related --\u003e\n\n\u003c!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. --\u003e\n\n\n\u003csection class=\"main-repo\" \u003e\n\n* * *\n\n## Notice\n\nThis package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.\n\nFor more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].\n\n#### Community\n\n[![Chat][chat-image]][chat-url]\n\n---\n\n## License\n\nSee [LICENSE][stdlib-license].\n\n\n## Copyright\n\nCopyright \u0026copy; 2016-2025. The Stdlib [Authors][stdlib-authors].\n\n\u003c/section\u003e\n\n\u003c!-- /.stdlib --\u003e\n\n\u003c!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. --\u003e\n\n\u003csection class=\"links\"\u003e\n\n[npm-image]: http://img.shields.io/npm/v/@stdlib/utils-fifo.svg\n[npm-url]: https://npmjs.org/package/@stdlib/utils-fifo\n\n[test-image]: https://github.com/stdlib-js/utils-fifo/actions/workflows/test.yml/badge.svg?branch=main\n[test-url]: https://github.com/stdlib-js/utils-fifo/actions/workflows/test.yml?query=branch:main\n\n[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/utils-fifo/main.svg\n[coverage-url]: https://codecov.io/github/stdlib-js/utils-fifo?branch=main\n\n\u003c!--\n\n[dependencies-image]: https://img.shields.io/david/stdlib-js/utils-fifo.svg\n[dependencies-url]: https://david-dm.org/stdlib-js/utils-fifo/main\n\n--\u003e\n\n[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg\n[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im\n\n[stdlib]: https://github.com/stdlib-js/stdlib\n\n[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors\n\n[umd]: https://github.com/umdjs/umd\n[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules\n\n[deno-url]: https://github.com/stdlib-js/utils-fifo/tree/deno\n[deno-readme]: https://github.com/stdlib-js/utils-fifo/blob/deno/README.md\n[umd-url]: https://github.com/stdlib-js/utils-fifo/tree/umd\n[umd-readme]: https://github.com/stdlib-js/utils-fifo/blob/umd/README.md\n[esm-url]: https://github.com/stdlib-js/utils-fifo/tree/esm\n[esm-readme]: https://github.com/stdlib-js/utils-fifo/blob/esm/README.md\n[branches-url]: https://github.com/stdlib-js/utils-fifo/blob/main/branches.md\n\n[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/utils-fifo/main/LICENSE\n\n\u003c!-- \u003crelated-links\u003e --\u003e\n\n[@stdlib/utils/stack]: https://github.com/stdlib-js/utils-stack\n\n\u003c!-- \u003c/related-links\u003e --\u003e\n\n\u003c/section\u003e\n\n\u003c!-- /.links --\u003e\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fstdlib-js%2Futils-fifo","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fstdlib-js%2Futils-fifo","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fstdlib-js%2Futils-fifo/lists"}