README

W3C HTML Validator

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';

or invoke directly from the command line or from a package.json script.

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

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.*
`ignoreMessages`	string or regex	`null`	Skip messages containing a string or matching a regular expression.*
`output`	`'json'` or `'html'`	`'json'`	Get results as an array or as a web page.

*The ignoreMessages and ignoreLevel options only work for 'json' output. Option value '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

Example CLI usage:

$ npm install --save-dev w3c-html-validator
$ npx w3c-html-validator docs/*.html flyer.html
$ npx w3c-html-validator docs  #validate html files in a folder
$ npx w3c-html-validator  #validate all html files in project

or as an npm script in package.json:

   "scripts": {
      "validate": "w3c-html-validator docs/*.html flyer.html",
      "folder":   "w3c-html-validator docs",
      "all":      "w3c-html-validator"
   },

Passing no parameters defaults to validating all HTML files in the projects (skipping the node_modules folder).

7) Gulp Task

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

Usage no npm install needed!