{"id":28964527,"url":"https://github.com/stdlib-js/dstructs-struct","last_synced_at":"2025-07-23T19:32:02.566Z","repository":{"id":299547843,"uuid":"1003382356","full_name":"stdlib-js/dstructs-struct","owner":"stdlib-js","description":"Fixed-width composite data type (a.k.a., a `struct`).","archived":false,"fork":false,"pushed_at":"2025-06-30T03:23:33.000Z","size":1080,"stargazers_count":0,"open_issues_count":0,"forks_count":0,"subscribers_count":0,"default_branch":"main","last_synced_at":"2025-07-09T09:45:05.515Z","etag":null,"topics":["c","composite","data","data-structure","data-structures","dataview","fixed-width","javascript","node","node-js","nodejs","stdlib","structure","type"],"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":"2025-06-17T04:19:16.000Z","updated_at":"2025-06-30T02:01:45.000Z","dependencies_parsed_at":"2025-06-17T05:27:49.087Z","dependency_job_id":"c2775976-5a0f-41fe-a10a-34eae3f769a8","html_url":"https://github.com/stdlib-js/dstructs-struct","commit_stats":null,"previous_names":["stdlib-js/dstructs-struct"],"tags_count":0,"template":false,"template_full_name":null,"purl":"pkg:github/stdlib-js/dstructs-struct","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Fdstructs-struct","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Fdstructs-struct/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Fdstructs-struct/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Fdstructs-struct/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/stdlib-js","download_url":"https://codeload.github.com/stdlib-js/dstructs-struct/tar.gz/refs/heads/main","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Fdstructs-struct/sbom","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":266738301,"owners_count":23976414,"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":"2025-07-23T02:00:09.312Z","response_time":66,"last_error":null,"robots_txt_status":null,"robots_txt_updated_at":null,"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":["c","composite","data","data-structure","data-structures","dataview","fixed-width","javascript","node","node-js","nodejs","stdlib","structure","type"],"created_at":"2025-06-24T05:06:39.667Z","updated_at":"2025-07-23T19:32:02.539Z","avatar_url":"https://github.com/stdlib-js.png","language":"JavaScript","readme":"\u003c!--\n\n@license Apache-2.0\n\nCopyright (c) 2025 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# struct\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 Fixed-width composite data type (a.k.a., a `struct`).\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/dstructs-struct\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 struct = require( '@stdlib/dstructs-struct' );\n```\n\n#### struct( schema )\n\nReturns a constructor for creating a fixed-width composite data type (a.k.a., a `struct`).\n\n```javascript\nvar fields = [\n    {\n        'type': 'union',\n        'fields': [\n            {\n                'name': 'double',\n                'description': 'double-precision floating-point number',\n                'type': 'float64',\n                'enumerable': true,\n                'writable': true,\n                'castingMode': 'none'\n            },\n            {\n                'name': 'words',\n                'description': 'high and low words',\n                'type': 'uint32',\n                'length': 2,\n                'enumerable': true,\n                'writable': true,\n                'castingMode': 'none'\n            }\n        ]\n    }\n];\nvar Struct = struct( fields );\n\nvar data = {\n    'double': 3.14\n};\nvar s = new Struct( data );\n// returns \u003cStruct\u003e\n\nvar v = s.double;\n// returns 3.14\n\nvar w = s.words;\n// e.g., \u003cUint32Array\u003e[ 1374389535, 1074339512 ]\n```\n\nTODO: document schema\n\nTODO: document constructor API\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-   While struct instances aim to emulate C `struct` behavior, structs have the following differences:\n\n    -   The struct schema supports default values. In C, uninitialized members are zero-filled.\n    -   The struct schema supports \"casting modes\", which govern member assignment operations and support placing (or relaxing) strict requirements on what types of values may be assigned to struct members. In C, members have no such limitations, with the C compiler performing implicit casting (e.g., a signed integer will be implicitly cast to an unsigned integer when a member has an unsigned integer data type).\n    -   Only fixed-width types are supported (e.g., `int8`, `float64`, etc). In C, members can have types which may vary across platforms (e.g., `int`, `enum`, `long double`, etc).\n    -   Member types must be serializable to an ArrayBuffer (e.g., no functions, general objects, etc). In C, members have no such limitations (e.g., a member can be a function pointer).\n    -   Union types must all have the same byte length. In C, members of union types can have different byte lengths.\n    -   struct instances can have \"hidden\" (i.e., non-enumerable) fields. In C, all members are part of a `struct`'s public API.\n    -   struct instances can have read-only fields. In C, one can use a `const` qualifier to prevent assignment after initialization; however, one can circumvent this restriction using pointer tricks.\n    -   Member types can have an associated description, which is useful when wanting to inspect struct instances in interactive contexts, such as REPLs.\n    -   struct instances support string and JSON serialization.\n\n-   A primary use case for emulating C `struct` behavior is to facilitate interoperation between JavaScript and C. For example, by creating a JavaScript struct instance which has the same alignment and layout as a C `struct`, one can pass a pointer to a struct instance's underlying byte buffer from JavaScript to C and then simply perform a cast to interpret as an equivalent C `struct`. This enables zero-copy interchange when, e.g., calling into Node.js native native add-ons and can greatly reduce overhead when working with heterogeneous composite data types.\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 Float64Array = require( '@stdlib/array-float64' );\nvar struct = require( '@stdlib/dstructs-struct' );\n\nvar fields = [\n    {\n        'name': 'rejected',\n        'description': 'boolean indicating whether the null hypothesis was rejected',\n        'type': 'bool',\n        'enumerable': true,\n        'writable': false,\n        'castingMode': 'none'\n    },\n    {\n        'name': 'alpha',\n        'description': 'significance level',\n        'type': 'float64',\n        'enumerable': true,\n        'writable': false,\n        'castingMode': 'mostly-safe'\n    },\n    {\n        'name': 'pValue',\n        'description': 'p-value',\n        'type': 'float64',\n        'enumerable': true,\n        'writable': false,\n        'castingMode': 'mostly-safe'\n    },\n    {\n        'name': 'statistic',\n        'description': 'test statistic',\n        'type': 'float64',\n        'writable': false,\n        'castingMode': 'mostly-safe'\n    },\n    {\n        'name': 'ci',\n        'description': 'confidence interval',\n        'type': 'float64',\n        'length': 2,\n        'enumerable': true,\n        'writable': false,\n        'castingMode': 'mostly-safe'\n    },\n    {\n        'name': 'df',\n        'description': 'degrees of freedom',\n        'type': 'int32',\n        'enumerable': true,\n        'writable': false,\n        'castingMode': 'mostly-safe'\n    },\n    {\n        'name': 'nullValue',\n        'description': 'null value',\n        'type': 'float64',\n        'enumerable': true,\n        'writable': false,\n        'castingMode': 'mostly-safe'\n    },\n    {\n        'name': 'mean',\n        'description': 'computed mean',\n        'type': 'float64',\n        'enumerable': true,\n        'writable': false,\n        'castingMode': 'mostly-safe'\n    },\n    {\n        'name': 'sd',\n        'description': 'standard error of the mean',\n        'type': 'float64',\n        'enumerable': true,\n        'writable': false,\n        'castingMode': 'mostly-safe'\n    }\n];\n\nvar Struct = struct( fields );\n\nvar s = new Struct({\n    'rejected': true,\n    'alpha': 0.05,\n    'pValue': 0.01,\n    'statistic': 3.14,\n    'ci': new Float64Array( [ -5.0, 5.0 ] ),\n    'df': 10,\n    'nullValue': 1.0,\n    'mean': 1.01,\n    'sd': 0.025\n});\n// returns \u003cStruct\u003e\n\nvar byteLength = Struct.byteLength;\nconsole.log( 'Byte length: %d', byteLength );\n\nvar alignment = Struct.alignment;\nconsole.log( 'Alignment: %d', alignment );\n\nvar names = Struct.fields;\nconsole.log( 'Field names: %s', names.join( ', ' ) );\n\nvar str = s.toString({\n    'format': 'linear'\n});\nconsole.log( 'String:\\n%s', str );\n\nvar o = s.toJSON();\nconsole.log( o );\n\nvar offset = Struct.byteOffsetOf( 'alpha' );\nconsole.log( 'Offset: %d', offset );\n\nvar desc = Struct.descriptionOf( 'alpha' );\nconsole.log( 'Description: %s', desc );\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\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/dstructs-struct.svg\n[npm-url]: https://npmjs.org/package/@stdlib/dstructs-struct\n\n[test-image]: https://github.com/stdlib-js/dstructs-struct/actions/workflows/test.yml/badge.svg?branch=main\n[test-url]: https://github.com/stdlib-js/dstructs-struct/actions/workflows/test.yml?query=branch:main\n\n[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/dstructs-struct/main.svg\n[coverage-url]: https://codecov.io/github/stdlib-js/dstructs-struct?branch=main\n\n\u003c!--\n\n[dependencies-image]: https://img.shields.io/david/stdlib-js/dstructs-struct.svg\n[dependencies-url]: https://david-dm.org/stdlib-js/dstructs-struct/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/dstructs-struct/tree/deno\n[deno-readme]: https://github.com/stdlib-js/dstructs-struct/blob/deno/README.md\n[umd-url]: https://github.com/stdlib-js/dstructs-struct/tree/umd\n[umd-readme]: https://github.com/stdlib-js/dstructs-struct/blob/umd/README.md\n[esm-url]: https://github.com/stdlib-js/dstructs-struct/tree/esm\n[esm-readme]: https://github.com/stdlib-js/dstructs-struct/blob/esm/README.md\n[branches-url]: https://github.com/stdlib-js/dstructs-struct/blob/main/branches.md\n\n[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/dstructs-struct/main/LICENSE\n\n\u003c/section\u003e\n\n\u003c!-- /.links --\u003e\n","funding_links":["https://github.com/sponsors/stdlib-js","https://opencollective.com/stdlib","https://tidelift.com/funding/github/npm/@stdlib/stdlib"],"categories":[],"sub_categories":[],"project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fstdlib-js%2Fdstructs-struct","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fstdlib-js%2Fdstructs-struct","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fstdlib-js%2Fdstructs-struct/lists"}