modernizr/src/testRunner.js

Modernizr is a JavaScript library that detects HTML5 and CSS3 features in the user’s browser.

define(['tests', 'Modernizr', 'classes', 'is'], function( tests, Modernizr, classes, is ) {
  // Run through all tests and detect their support in the current UA.
  function testRunner() {
    var featureNames;
    var feature;
    var aliasIdx;
    var result;
    var nameIdx;
    for ( var featureIdx in tests ) {
      featureNames = [];
      feature = tests[featureIdx];
      // run the test, throw the return value into the Modernizr,
      //   then based on that boolean, define an appropriate className
      //   and push it into an array of classes we'll join later.
      //
      //   If there is no name, it's an 'async' test that is run,
      //   but not directly added to the object. That should
      //   be done with a post-run addTest call.
      if ( feature.name ) {
        featureNames.push(feature.name.toLowerCase());

        if (feature.options && feature.options.aliases && feature.options.aliases.length) {
          // Add all the aliases into the names list
          for (aliasIdx = 0; aliasIdx < feature.options.aliases.length; aliasIdx++) {
            featureNames.push(feature.options.aliases[aliasIdx].toLowerCase());
          }
        }
      }

      // Run the test, or use the raw value if it's not a function
      result = is(feature.fn, 'function') ? feature.fn() : feature.fn;

      // Set each of the names on the Modernizr object
      for (nameIdx = 0; nameIdx < featureNames.length; nameIdx++) {
        Modernizr[featureNames[nameIdx]] = result;
        classes.push((Modernizr[featureNames[nameIdx]] ? '' : 'no-') + featureNames[nameIdx]);
      }
    }
  }

  return testRunner;
});