utf-8-validate
Check if a buffer contains valid UTF-8
About
Check if a buffer contains valid UTF-8
Live mirror of the GitHub README. Updated whenever the repo's default branch changes.
utf-8-validate
Check if a buffer contains valid UTF-8 encoded text.
Installation
npm install utf-8-validate --save-optional
The --save-optional flag tells npm to save the package in your package.json
under the
optionalDependencies
key.
API
The module exports a single function that takes one argument. To maximize performance, the argument is not validated. It is the caller's responsibility to ensure that it is correct.
isValidUTF8(buffer)
Checks whether a buffer contains valid UTF-8.
Arguments
buffer- The buffer to check.
Return value
true if the buffer contains only correct UTF-8, else false.
Example
'use strict';
const isValidUTF8 = require('utf-8-validate');
const buf = Buffer.from([0xf0, 0x90, 0x80, 0x80]);
console.log(isValidUTF8(buf));
// => true
License
Quick facts
npm install utf-8-validateHow Sourcemap Explorer detects utf-8-validate
We catch utf-8-validate from two complementary signals: bundled source paths and the embedded package.json. Modern bundlers (webpack, Vite, esbuild, Rollup, Turbopack) preserve the original node_modules/utf-8-validate/ paths inside the JavaScript sourcemap's sources[] array — that's the canonical signal. When the matching package.json is also captured in sourcesContent[], we read the exact version field — patch number included. No regex guessing, no version inference.
- 1
Confirm the site exposes sourcemaps
In DevTools Network, check the response headers of any application script for `SourceMap` or `X-SourceMap`. Failing that, fetch the script's last 4 KB and look for a `//# sourceMappingURL=` comment.
- 2
Find the package in the bundle
Open DevTools → Network → reload. Click any application script and look at its sourcemap. Inside, search `sources[]` for entries matching `node_modules/utf-8-validate/` — every match confirms the package is bundled. The matching `sourcesContent[i]` for `node_modules/utf-8-validate/package.json` gives you the exact installed version.
- 3
Read the version directly from package.json
Run `jq -r '. as $m | $m.sources | to_entries[] | select(.value | endswith("node_modules/utf-8-validate/package.json")) | $m.sourcesContent[.key] | fromjson | .version' bundle.js.map`. Sourcemap Explorer automates the same query in the popup.
Recent versions
FAQ
What is utf-8-validate used for?
Check if a buffer contains valid UTF-8
How can I tell if a website is using utf-8-validate?
Open the page in Chrome with the Sourcemap Explorer extension installed and read the Stack tab. We catch `utf-8-validate` from two complementary signals: `node_modules/utf-8-validate/` paths inside the JavaScript sourcemap, and the embedded `package.json` we read for exact-version detection. Without the extension you can do the same lookup manually in DevTools — the steps are listed in the "How Sourcemap Explorer detects" section above.
What is the latest version of utf-8-validate?
6.0.6, as published on the npm registry. The "Recent versions" table on this page lists the most recent 8 releases with their release dates. Sourcemap Explorer reports the version actually bundled into a site, which can lag the latest release by months on real-world deployments.
Where can I read more?
Project homepage: https://github.com/websockets/utf-8-validate. Source code: https://github.com/websockets/utf-8-validate. Published on npm: https://www.npmjs.com/package/utf-8-validate. Licensed as MIT.
Detected by Sourcemap Explorer
When a bundle ships sourcemaps, we read the embedded package.json for utf-8-validate and report the precise version. Without sourcemaps, an import / require in the page's scripts is enough to flag it.