Test if a value is a URI.
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> Test if a value is a [URI][uri].
``bash`
npm install @stdlib/assert-is-uri
`javascript`
var isURI = require( '@stdlib/assert-is-uri' );
#### isURI( value )
Tests if a value is a [URI][uri].
`javascript
var bool = isURI( 'https://google.com' );
// returns true
bool = isURI( 'ftp://ftp.is.co.za/rfc/rfc1808.txt' );
// returns true
bool = isURI( '' );
// returns false
bool = isURI( 'foo' );
// returns false
bool = isURI( null );
// returns false
bool = isURI( NaN );
// returns false
bool = isURI( true );
// returns false
`
- For more information regarding the URI scheme, see [RFC 3986][rfc-3986] and [Wikipedia][uri].
- On the distinction between URI, URL, and URN, see [The Difference Between URLs and URIs][difference-url-uri].
`javascript
var isURI = require( '@stdlib/assert-is-uri' );
/ Valid /
var bool = isURI( 'http://google.com' );
// returns true
bool = isURI( 'http://localhost/' );
// returns true
bool = isURI( 'http://example.w3.org/path%20with%20spaces.html' );
// returns true
bool = isURI( 'http://example.w3.org/%20' );
// returns true
bool = isURI( 'ftp://ftp.is.co.za/rfc/rfc1808.txt' );
// returns true
bool = isURI( 'ftp://ftp.is.co.za/../../../rfc/rfc1808.txt' );
// returns true
bool = isURI( 'http://www.ietf.org/rfc/rfc2396.txt' );
// returns true
bool = isURI( 'ldap://[2001:db8::7]/c=GB?objectClass?one' );
// returns true
bool = isURI( 'mailto:John.Doe@example.com' );
// returns true
bool = isURI( 'news:comp.infosystems.www.servers.unix' );
// returns true
bool = isURI( 'tel:+1-816-555-1212' );
// returns true
bool = isURI( 'telnet://192.0.2.16:80/' );
// returns true
bool = isURI( 'urn:oasis:names:specification:docbook:dtd:xml:4.1.2' );
// returns true
/ Invalid /
// No scheme:
bool = isURI( '' );
// returns false
// No scheme:
bool = isURI( 'foo' );
// returns false
// No scheme:
bool = isURI( 'foo@bar' );
// returns false
// No scheme:
bool = isURI( '://foo/' );
// returns false
// Illegal characters:
bool = isURI( 'http://
// returns false
// Invalid path:
bool = isURI( 'http:////foo.html' );
// returns false
// Incomplete hex escapes...
bool = isURI( 'http://example.w3.org/%a' );
// returns false
bool = isURI( 'http://example.w3.org/%a/foo' );
// returns false
bool = isURI( 'http://example.w3.org/%at' );
// returns false
`
- [@stdlib/assert-is-uri-cli][@stdlib/assert-is-uri-cli]: CLI package for use as a command-line utility.
*
This 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.
For 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].
#### Community
[![Chat][chat-image]][chat-url]
---
See [LICENSE][stdlib-license].
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
[@stdlib/assert-is-uri-cli]: https://www.npmjs.com/package/@stdlib/assert-is-uri-cli
[npm-image]: http://img.shields.io/npm/v/@stdlib/assert-is-uri.svg
[npm-url]: https://npmjs.org/package/@stdlib/assert-is-uri
[test-image]: https://github.com/stdlib-js/assert-is-uri/actions/workflows/test.yml/badge.svg?branch=v0.2.3
[test-url]: https://github.com/stdlib-js/assert-is-uri/actions/workflows/test.yml?query=branch:v0.2.3
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/assert-is-uri/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/assert-is-uri?branch=main
[chat-image]: https://img.shields.io/badge/zulip-join_chat-brightgreen.svg
[chat-url]: https://stdlib.zulipchat.com
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[cli-section]: https://github.com/stdlib-js/assert-is-uri#cli
[cli-url]: https://github.com/stdlib-js/assert-is-uri/tree/cli
[@stdlib/assert-is-uri]: https://github.com/stdlib-js/assert-is-uri/tree/main
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/assert-is-uri/tree/deno
[deno-readme]: https://github.com/stdlib-js/assert-is-uri/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/assert-is-uri/tree/umd
[umd-readme]: https://github.com/stdlib-js/assert-is-uri/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/assert-is-uri/tree/esm
[esm-readme]: https://github.com/stdlib-js/assert-is-uri/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/assert-is-uri/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/assert-is-uri/main/LICENSE
[uri]: https://en.wikipedia.org/wiki/URI_scheme
[rfc-3986]: https://tools.ietf.org/html/rfc3986
[difference-url-uri]: https://danielmiessler.com/study/url-uri/
[standard-streams]: https://en.wikipedia.org/wiki/Standard_streams
[mdn-regexp]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions