{"id":25931152,"url":"https://github.com/stdlib-js/utils-async-inmap-right","last_synced_at":"2026-04-08T14:05:00.810Z","repository":{"id":41427322,"uuid":"376835263","full_name":"stdlib-js/utils-async-inmap-right","owner":"stdlib-js","description":"Invoke a function for each element in a collection and update the collection in-place, iterating from right to left.","archived":false,"fork":false,"pushed_at":"2025-06-30T02:28:24.000Z","size":987,"stargazers_count":1,"open_issues_count":0,"forks_count":0,"subscribers_count":3,"default_branch":"main","last_synced_at":"2025-06-30T03:22:35.415Z","etag":null,"topics":["array","array-like","async","asynchronous","collection","in-place","inmap","iterate","javascript","map","mutate","node","node-js","nodejs","right","stdlib","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":"2021-06-14T13:36:32.000Z","updated_at":"2025-06-30T02:04:04.000Z","dependencies_parsed_at":"2023-09-23T19:00:19.074Z","dependency_job_id":"4dcba0be-150e-41e9-b4fe-8880a61b42f8","html_url":"https://github.com/stdlib-js/utils-async-inmap-right","commit_stats":{"total_commits":56,"total_committers":2,"mean_commits":28.0,"dds":"0.017857142857142905","last_synced_commit":"78895d1710a2e1cae00132e3098a9c20efbf3329"},"previous_names":[],"tags_count":24,"template":false,"template_full_name":null,"purl":"pkg:github/stdlib-js/utils-async-inmap-right","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Futils-async-inmap-right","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Futils-async-inmap-right/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Futils-async-inmap-right/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Futils-async-inmap-right/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/stdlib-js","download_url":"https://codeload.github.com/stdlib-js/utils-async-inmap-right/tar.gz/refs/heads/main","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Futils-async-inmap-right/sbom","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":264646891,"owners_count":23643505,"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","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":["array","array-like","async","asynchronous","collection","in-place","inmap","iterate","javascript","map","mutate","node","node-js","nodejs","right","stdlib","util","utilities","utility","utils"],"created_at":"2025-03-03T23:58:07.218Z","updated_at":"2026-04-08T14:05:00.804Z","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# inmapRightAsync\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 Invoke a function for each element in a collection and update the collection in-place, iterating from right to left.\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-async-inmap-right\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 inmapRightAsync = require( '@stdlib/utils-async-inmap-right' );\n```\n\n#### inmapRightAsync( collection, \\[options,] fcn, done )\n\nInvokes a function for each element in a `collection` and updates the `collection` in-place, iterating from right to left.\n\n\u003c!-- eslint-disable no-use-before-define --\u003e\n\n```javascript\nfunction fcn( value, index, next ) {\n    setTimeout( onTimeout, value );\n    function onTimeout() {\n        console.log( value );\n        next( null, value*index );\n    }\n}\n\nfunction done( error, collection ) {\n    if ( error ) {\n        throw error;\n    }\n    console.log( collection === arr );\n    console.log( collection );\n}\n\nvar arr = [ 1000, 2500, 3000 ];\n\ninmapRightAsync( arr, fcn, done );\n/*\n    1000\n    2500\n    3000\n    true\n    [ 0, 2500, 6000 ]\n*/\n```\n\nThe `next` callback accepts two arguments: `error` and `result`. The second argument to the `next` callback is used to update the `collection` element for the corresponding collection `index`, thus mutating the input `collection`.\n\n```javascript\nfunction fcn( value, index, next ) {\n    setTimeout( onTimeout, value );\n    function onTimeout() {\n        next( null, 'beep: '+index );\n    }\n}\n\nfunction done( error, collection ) {\n    if ( error ) {\n        throw error;\n    }\n    console.log( collection );\n    // =\u003e [ 'beep: 0', 'beep: 1', 'beep: 2' ]\n}\n\nvar arr = [ 1000, 2500, 3000 ];\n\ninmapRightAsync( arr, fcn, done );\n```\n\nIf the `next` callback is called with an `error` argument, the input `collection` may be **partially** mutated.\n\n```javascript\nfunction fcn( value, index, next ) {\n    setTimeout( onTimeout, value );\n    function onTimeout() {\n        if ( index === 1 ) {\n            return next( new Error( 'boop' ) );\n        }\n        next( null, 'beep: '+index );\n    }\n}\n\nfunction done( error, collection ) {\n    if ( error ) {\n        // Ignore error...\n    }\n    console.log( collection );\n    // =\u003e [ 1000, 2000, 'beep: 2' ]\n}\n\nvar arr = [ 1000, 2000, 3000 ];\n\ninmapRightAsync( arr, fcn, done );\n```\n\nThe function accepts the following `options`:\n\n-   **limit**: the maximum number of pending invocations at any one time. Default: `infinity`.\n-   **series**: boolean indicating whether to sequentially invoke `fcn` for each `collection` element. If `true`, the function sets `options.limit=1`. Default: `false`.\n-   **thisArg**: the execution context for `fcn`.\n\nBy default, all elements are processed concurrently, which means that the function does **not** guarantee completion order. To process each `collection` element sequentially, set the `series` option to `true`.\n\n\u003c!-- eslint-disable no-use-before-define --\u003e\n\n```javascript\nfunction fcn( value, index, next ) {\n    setTimeout( onTimeout, value );\n    function onTimeout() {\n        console.log( value );\n        next( null, value*index );\n    }\n}\n\nfunction done( error, collection ) {\n    if ( error ) {\n        throw error;\n    }\n    console.log( collection === arr );\n    console.log( collection );\n}\n\nvar arr = [ 1000, 2500, 3000 ];\n\nvar opts = {\n    'series': true\n};\n\ninmapRightAsync( arr, opts, fcn, done );\n/* =\u003e\n    3000\n    2500\n    1000\n    true\n    [ 0, 2500, 6000 ]\n*/\n```\n\nTo limit the maximum number of pending function invocations, set the `limit` option.\n\n\u003c!-- eslint-disable no-use-before-define --\u003e\n\n```javascript\nfunction fcn( value, index, next ) {\n    setTimeout( onTimeout, value );\n    function onTimeout() {\n        console.log( value );\n        next( null, value*index );\n    }\n}\n\nfunction done( error, collection ) {\n    if ( error ) {\n        throw error;\n    }\n    console.log( collection === arr );\n    console.log( collection );\n}\n\nvar arr = [ 1000, 2500, 3000 ];\n\nvar opts = {\n    'limit': 2\n};\n\ninmapRightAsync( arr, opts, fcn, done );\n/* =\u003e\n    2500\n    3000\n    1000\n    true,\n    [ 0, 2500, 6000 ]\n*/\n```\n\nTo set the execution context of `fcn`, set the `thisArg` option.\n\n\u003c!-- eslint-disable no-use-before-define --\u003e\n\n```javascript\nfunction fcn( value, index, next ) {\n    this.count += 1;\n    setTimeout( onTimeout, value );\n    function onTimeout() {\n        next( null, value*index );\n    }\n}\n\nvar arr = [ 1000, 2500, 3000 ];\n\nvar context = {\n    'count': 0\n};\n\nvar opts = {\n    'thisArg': context\n};\n\ninmapRightAsync( arr, opts, fcn, done );\n\nfunction done( error, collection ) {\n    if ( error ) {\n        throw error;\n    }\n    console.log( collection === arr );\n    // =\u003e true\n\n    console.log( collection );\n    // =\u003e [ 0, 2500, 6000 ]\n\n    console.log( context.count );\n    // =\u003e 3\n}\n```\n\nWhen invoked, `fcn` is provided a maximum of four arguments:\n\n-   **value**: collection value.\n-   **index**: collection index.\n-   **collection**: the input `collection`.\n-   **next**: a callback which should be called once `fcn` has finished processing a collection `value`.\n\nThe actual number of provided arguments depends on function `length`. If `fcn` accepts two arguments, `fcn` is provided `value` and `next`. If `fcn` accepts three arguments, `fcn` is provided `value`, `index`, and `next`. For every other `fcn` signature, `fcn` is provided all four arguments.\n\n\u003c!-- eslint-disable no-use-before-define --\u003e\n\n```javascript\nfunction fcn( value, i, collection, next ) {\n    console.log( 'collection: %s. %d: %d', collection.join( ',' ), i, value );\n    setTimeout( onTimeout, value );\n    function onTimeout() {\n        console.log( value );\n        next( null, value*i );\n    }\n}\n\nfunction done( error, collection ) {\n    if ( error ) {\n        throw error;\n    }\n    console.log( collection === arr );\n    console.log( collection );\n}\n\nvar arr = [ 1000, 2500, 3000 ];\n\ninmapRightAsync( arr, fcn, done );\n/* =\u003e\n    collection: 3000,2500,1000. 2: 3000\n    collection: 3000,2500,1000. 1: 2500\n    collection: 3000,2500,1000. 0: 1000\n    1000\n    2500\n    3000\n    true\n    [ 0, 2500, 6000 ]\n*/\n```\n\n#### inmapRightAsync.factory( \\[options,] fcn )\n\nReturns a function which invokes a function once for each element in a `collection`, iterating from right to left.\n\n```javascript\nfunction fcn( value, index, next ) {\n    setTimeout( onTimeout, value );\n    function onTimeout() {\n        console.log( value );\n        next( null, value*index );\n    }\n}\n\nfunction done( error, collection ) {\n    if ( error ) {\n        throw error;\n    }\n    console.log( collection );\n}\n\nvar f = inmapRightAsync.factory( fcn );\n\nvar arr1 = [ 1000, 2500, 3000 ];\n\nf( arr1, done );\n/* =\u003e\n    1000\n    2500\n    3000\n    [ 0, 2500, 6000 ]\n*/\n\nvar arr2 = [ 100, 250, 300 ];\n\nf( arr2, done );\n/* =\u003e\n    100\n    250\n    300\n    [ 0, 250, 600 ]\n*/\n```\n\nThe function accepts the same `options` as `inmapRightAsync()`.\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## Notes\n\n-   A `collection` may be either an [`Array`][mdn-array], [`Typed Array`][mdn-typed-array], or an array-like [`Object`][mdn-object] (excluding `strings` and `functions`).\n-   If a provided function calls the `next` callback with a truthy `error` argument, the function suspends execution and immediately calls the `done` callback for subsequent `error` handling.\n-   The function invokes the `done` callback with the input `collection` provided as the second argument.\n-   The function modifies `collection` elements in-place.\n-   The function does **not** support dynamic `collection` resizing.\n-   The function does **not** skip `undefined` elements.\n-   **Neither** `inmapRightAsync` nor the function returned by the `factory` method **guarantee** asynchronous execution. To guarantee asynchrony, wrap the `done` callback in a function which either executes at the end of the current stack (e.g., `nextTick`) or during a subsequent turn of the event loop (e.g., `setImmediate`, `setTimeout`).\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 resolve = require( 'path' ).resolve;\nvar readFile = require( '@stdlib/fs-read-file' );\nvar inmapRightAsync = require( '@stdlib/utils-async-inmap-right' );\n\nvar files = [\n    resolve( __dirname, 'package.json' ),\n    resolve( __dirname, 'README.md' )\n];\n\nfunction done( error, results ) {\n    if ( error ) {\n        throw error;\n    }\n    console.log( results );\n}\n\nfunction read( file, next ) {\n    var opts = {\n        'encoding': 'utf8'\n    };\n    readFile( file, opts, onFile );\n\n    function onFile( error, data ) {\n        if ( error ) {\n            error = new Error( 'unable to read file: '+file );\n            return next( error );\n        }\n        next( null, data );\n    }\n}\n\ninmapRightAsync( files, read, done );\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-async/for-each-right`][@stdlib/utils/async/for-each-right]\u003c/span\u003e\u003cspan class=\"delimiter\"\u003e: \u003c/span\u003e\u003cspan class=\"description\"\u003einvoke a function once for each element in a collection, iterating from right to left.\u003c/span\u003e\n-   \u003cspan class=\"package-name\"\u003e[`@stdlib/utils-async/inmap`][@stdlib/utils/async/inmap]\u003c/span\u003e\u003cspan class=\"delimiter\"\u003e: \u003c/span\u003e\u003cspan class=\"description\"\u003einvoke a function for each element in a collection and update the collection in-place.\u003c/span\u003e\n-   \u003cspan class=\"package-name\"\u003e[`@stdlib/utils-inmap-right`][@stdlib/utils/inmap-right]\u003c/span\u003e\u003cspan class=\"delimiter\"\u003e: \u003c/span\u003e\u003cspan class=\"description\"\u003einvoke a function for each element in a collection and update the collection in-place, iterating from right to left.\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; 2016-2026. 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-async-inmap-right.svg\n[npm-url]: https://npmjs.org/package/@stdlib/utils-async-inmap-right\n\n[test-image]: https://github.com/stdlib-js/utils-async-inmap-right/actions/workflows/test.yml/badge.svg?branch=main\n[test-url]: https://github.com/stdlib-js/utils-async-inmap-right/actions/workflows/test.yml?query=branch:main\n\n[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/utils-async-inmap-right/main.svg\n[coverage-url]: https://codecov.io/github/stdlib-js/utils-async-inmap-right?branch=main\n\n\u003c!--\n\n[dependencies-image]: https://img.shields.io/david/stdlib-js/utils-async-inmap-right.svg\n[dependencies-url]: https://david-dm.org/stdlib-js/utils-async-inmap-right/main\n\n--\u003e\n\n[chat-image]: https://img.shields.io/badge/zulip-join_chat-brightgreen.svg\n[chat-url]: https://stdlib.zulipchat.com\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-async-inmap-right/tree/deno\n[deno-readme]: https://github.com/stdlib-js/utils-async-inmap-right/blob/deno/README.md\n[umd-url]: https://github.com/stdlib-js/utils-async-inmap-right/tree/umd\n[umd-readme]: https://github.com/stdlib-js/utils-async-inmap-right/blob/umd/README.md\n[esm-url]: https://github.com/stdlib-js/utils-async-inmap-right/tree/esm\n[esm-readme]: https://github.com/stdlib-js/utils-async-inmap-right/blob/esm/README.md\n[branches-url]: https://github.com/stdlib-js/utils-async-inmap-right/blob/main/branches.md\n\n[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/utils-async-inmap-right/main/LICENSE\n\n[mdn-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array\n\n[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\n\n[mdn-object]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object\n\n\u003c!-- \u003crelated-links\u003e --\u003e\n\n[@stdlib/utils/async/for-each-right]: https://github.com/stdlib-js/utils-async-for-each-right\n\n[@stdlib/utils/async/inmap]: https://github.com/stdlib-js/utils-async-inmap\n\n[@stdlib/utils/inmap-right]: https://github.com/stdlib-js/utils-inmap-right\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-async-inmap-right","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fstdlib-js%2Futils-async-inmap-right","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fstdlib-js%2Futils-async-inmap-right/lists"}