w3c-html-validator

W3C HTML Validator

<img src=https://centerkey.com/graphics/center-key-logo.svg align=right width=200 alt=logo>

A package for testing HTML files or URLs against the W3C validator

1) Setup

Install

Install package for node:

$ npm install --save-dev w3c-html-validator

Import

Import into your application:

import { w3cHtmlValidator } from 'w3c-html-validator';

2) Usage

Call the validate() function:

const options = { filename: 'docs/index.html' };
w3cHtmlValidator.validate(options).then(console.log);

To display formatted output, replace console.log with w3cHtmlValidator.reporter:

w3cHtmlValidator.validate(options).then(w3cHtmlValidator.reporter);

To see some example validation results, run the commands:

$ cd w3c-html-validator
$ node examples.js

<img src=https://raw.githubusercontent.com/center-key/w3c-html-validator/main/examples.png width=800 alt=screenshot>

3) Options

validate()

Name (key)	Type	Default	Description
html	string	null	HTML string to validate.
filename	string	null	HTML file to validate.
website	string	null	URL of website to validate.
checkUrl	string	'https://validator.w3.org/nu/'	W3C validation API endpoint.
ignoreLevel	'info' or 'warning'	null	Skip unwanted messages.*
output	'json' or 'html'	'json'	Get results as an array or as a web page.
*The ignoreLevel option only works for 'json' output.  Leven 'warning' also skips 'info'.

reporter()

Name (key)	Type	Default	Description
maxMessageLen	number	null	Trim validation messages to not exceed a maximum length.
title	string	null	Override display title (useful for naming HTML string inputs).

4) TypeScript Declarations

The TypeScript Declaration File file is w3c-html-validator.d.ts in the dist folder.

The output of the w3cHtmlValidator.validate(options: ValidatorOptions) function is a promise for ValidatorResults object:

type ValidatorResults = {
   validates: boolean,
   mode:      'html' | 'filename' | 'website';
   html:      string | null,
   filename:  string | null,
   website:   string | null,
   output:    'json' | 'html',
   status:    number,
   messages:  ValidatorResultsMessage[] | null,  //for 'json' output
   display:   string | null,                     //for 'html' output
   };

5) Mocha Example

import assert from 'assert';
import { w3cHtmlValidator } from 'w3c-html-validator';

describe('Home page', () => {
   it('validates', (done) => {
      const handleResults = (results) => {
         assert(results.status === 200, 'Request succeeded');
         assert(results.validates, 'Home page validates');
         done();
         };
      const options = { filename: 'docs/index.html' };
      w3cHtmlValidator.validate(options).then(handleResults);
      });
   });

6) Command Line

$ npm install --save-dev w3c-html-validator
$ w3c-html-validator docs/index.html

or as an npm script in package.json:

   "scripts": {
      "validate": "w3c-html-validator docs/index.html",
   },

Note: This feature is currently just experimental.

7) Gulp Task

This library is available as a Gulp plugin:
https://github.com/center-key/gulp-w3c-html-validator