Repository: angular/angular.js
File: src/ng/compile.js (JavaScript)

Code before:
   *    - `controllerAs` – `{string=}` – identifier name for to reference the controller in the component's scope.
   *      If present, the controller will be published to scope under the `controllerAs` name.
   *      If not present, this will default to be `$ctrl`.
   *    - `template` – `{string=|function()=}` – html template as a string or a function that
   *      returns an html template as a string which should be used as the contents of this component.
   *      Empty string by default.
   *
   *      If `template` is a function, then it is {@link auto.$injector#invoke injected} with
   *      the following locals:
   *
   *      - `$element` - Current element
   *      - `$attrs` - Current attributes object for the element
   *
   *    - `templateUrl` – `{string=|function()=}` – path or function that returns a path to an html
   *      template that should be used  as the contents of this component.
   *
   *      If `templateUrl` is a function, then it is {@link auto.$injector#invoke injected} with
   *      the following locals:
   *
   *      - `$element` - Current element
   *      - `$attrs` - Current attributes object for the element
   *
   *    - `bindings` – `{object=}` – defines bindings between DOM attributes and component properties.
   *      Component properties are always bound to the component controller and not to the scope.
   *      See {@link ng.$compile#-bindtocontroller- `bindToController`}.
   *    - `transclude` – `{boolean=}` – whether {@link $compile#transclusion content transclusion} is enabled.
   *      Disabled by default.
   *    - `require` - `{Object<string, string>=}` - requires the controllers of other directives and binds them to
   *      this component's controller. The object keys specify the property names under which the required
   *      controllers (object values) will be bound. See {@link ng.$compile#-require- `require`}.
   *    - `$...` – additional properties to attach to the directive factory function and the controller
   *      constructor function. (This is used by the component router to annotate)
   *
   * @returns {ng.$compileProvider} the compile provider itself, for chaining of function calls.
   * @description
   * Register a **component definition** with the compiler. This is a shorthand for registering a special
   * type of directive, which represents a self-contained UI component in your application. Such components
   * are always isolated (i.e. `scope: {}`) and are always restricted to elements (i.e. `restrict: 'E'`).
   *
   * Component definitions are very simple and do not require as much configuration as defining general
   * directives. Component definitions usually consist only of a template and a controller backing it.
   *
   * In order to make the definition easier, components enforce best practices like use of `controllerAs`,
   * `bindToController`. They always have **isolate scope** and are restricted to elements.
   *
   * Here are a few examples of how you would usually define components:
   *
   * ```js
   *   var myMod = angular.module(...);
   *   myMod.component('myComp', {
   *     template: '<div>My name is {{$ctrl.name}}</div>',

Review comment (suggestion):
I've updated this to convert all falsey values to the default like previously.

Cases which previously logged errors per-compilation (of an attribute/element with the same name), but otherwise did nothing:
- non-string truthy values

Cases which previously silently did nothing:
- arrays without single-character E/A/C/M
- strings with only invalid characters

Cases that previously worked unintentionally:
- arrays with single-character entries of E/A/C/M (such as `['E', 'A']` but not `['EA']`)

Now all of these cases get logged as errors the first time an attribute/element of that name gets compiled.


Code after:
    if (!letter || letter !== lowercase(letter)) {
      throw $compileMinErr('baddir', 'Directive/Component name \'{0}\' is invalid. The first character must be a lowercase letter', name);
    }
    if (name !== name.trim()) {
      throw $compileMinErr('baddir',
            'Directive/Component name \'{0}\' is invalid. The name should not contain leading or trailing whitespaces',
            name);
    }
  }

  function getDirectiveRequire(directive) {
    var require = directive.require || (directive.controller && directive.name);

    if (!isArray(require) && isObject(require)) {
      forEach(require, function(value, key) {
        var match = value.match(REQUIRE_PREFIX_REGEXP);
        var name = value.substring(match[0].length);
        if (!name) require[key] = match[0] + key;
      });
    }

    return require;
  }

  function getDirectiveRestrict(restrict, name) {
    if (restrict && !(isString(restrict) && /[EACM]/.test(restrict))) {
      throw $compileMinErr('badrestrict',
          'Restrict property \'{0}\' of directive \'{1}\' is invalid',
          restrict,
          name);
    }

    return restrict || 'EA';
  }

  /**
   * @ngdoc method
   * @name $compileProvider#directive
   * @kind function
   *
   * @description
   * Register a new directive with the compiler.
   *
   * @param {string|Object} name Name of the directive in camel-case (i.e. <code>ngBind</code> which
   *    will match as <code>ng-bind</code>), or an object map of directives where the keys are the
   *    names and the values are the factories.
   * @param {Function|Array} directiveFactory An injectable directive factory function. See the
   *    {@link guide/directive directive guide} and the {@link $compile compile API} for more info.
   * @returns {ng.$compileProvider} Self for chaining.
   */
  this.directive = function registerDirective(name, directiveFactory) {