crawlkit-runner-accessibility-developer-tools/src/index.js

A CrawlKit runner for running the Google Chrome a11y developer tools

'use strict'; // eslint-disable-line
const path = require('path');

class A11yDeveloperToolsRunner {
  getCompanionFiles() {
    return [
      // ah, the things your eyes have seen now...
      path.join(__dirname, 'amd.undefine.js'),
      require.resolve(path.join('accessibility-developer-tools', 'dist', 'js', 'axs_testing.js')),
      require.resolve(path.join('html-context', 'dist', 'index.js')),
      path.join(__dirname, 'amd.redefine.js'),
    ];
  }

  getRunnable() {
    /* global axs:false, htmlContext:false */
    /* eslint-disable no-var, vars-on-top, no-console, object-shorthand */
    return function axsRunner() {
      var configuration = new axs.AuditConfiguration();
      configuration.showUnsupportedRulesWarning = false;
      var results = axs.Audit.run(configuration);

      /**
       * @param line {!String}  The error line, something like:
       *                        "
       *                        Warning: ERROR_CODE (Description) failed on the following element:
       *                        html
       *                        See https://link for more information
       *                        "
       */
      function parseError(line) {
        var lines = line.split('\n');
        var matches = lines.shift().match(
            /^.+?: ([A-Z0-9_]+) \((.*)\) failed on the following element.+$/
        );
        var urlMatches = lines.pop().match(
            /^See (.*) for more information\.$/
        );

        function selectorToContext(selector) {
          var context = null;
          if (selector) {
            var domElement = document.querySelector(selector);
            if (domElement instanceof window.HTMLElement) {
              try {
                context = htmlContext(domElement, {
                  maxLength: 255,
                });
              } catch (e) {
                console.error(e);
              }
            }
          }
          return {
            selector: selector,
            context: context,
          };
        }

        var ret = {
          code: matches[1],
          elements: lines.map(selectorToContext),
          msg: matches[2],
          helpUrl: urlMatches[1],
        };
        return ret;
      }

      function reformat(res) {
        if (!res) {
          return res;
        }

        return {
          errors: res.errors_.map(parseError),
          warnings: res.warnings_.map(parseError),
        };
      }

      window.callPhantom(null, reformat(axs.Audit.auditResults(results)));
    };
  }
}
module.exports = A11yDeveloperToolsRunner;