vnu-jar: Check HTML from JavaScript

vnu-jar lets you use the Nu Html Checker (vnu) from within JavaScript code — to catch unintended mistakes in HTML, CSS, and SVG content.

Install latest release version

npm install --save vnu-jar

Example

Here’s an example of how to create a simple vnu-check.js program that uses the vnu-jar package to invoke the Nu Html Checker (vnu), pass it whatever arguments the user specifies, and then emit the checker output.

'use strict';
const { vnu } = require('vnu-jar');
(async () => {
    try {
        console.log(await vnu.check(process.argv.slice(2)));
    } catch (err) {
        console.error(err.message.trim());
        process.exit(1);
    }
})();

Command-line usage

When installed or run via npx, the package also provides a vnu command that causes the vnu.jar program to be invoked and run with whatever arguments you specify:

npx vnu --verbose file1.html file2.html
npx vnu --help

Java auto-installation

This npm package includes the vnu.jar Java program — so to use the package, users will additionally need a Java environment that provides a java command.

For that reason, the package runs a postinstall script which — if it finds no java command in the user’s environment during install — will then automatically install a (Node.js-local) Java runtime environment, in node_modules/.cache/vnu-jar/java/).