From e69c2872939cda30f13a1a8390bbc61662c12d9a Mon Sep 17 00:00:00 2001 From: Brian Ford Date: Wed, 23 Oct 2013 14:04:47 -0700 Subject: docs(guide/directive,guide/compiler,): drastically improve --- src/ng/compile.js | 352 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 343 insertions(+), 9 deletions(-) (limited to 'src/ng/compile.js') diff --git a/src/ng/compile.js b/src/ng/compile.js index 7476b46b..2ff9144b 100644 --- a/src/ng/compile.js +++ b/src/ng/compile.js @@ -25,21 +25,355 @@ * * @description * Compiles a piece of HTML string or DOM into a template and produces a template function, which - * can then be used to link {@link ng.$rootScope.Scope scope} and the template together. + * can then be used to link {@link ng.$rootScope.Scope `scope`} and the template together. * - * The compilation is a process of walking the DOM tree and trying to match DOM elements to - * {@link ng.$compileProvider#methods_directive directives}. For each match it - * executes corresponding template function and collects the - * instance functions into a single template function which is then returned. + * The compilation is a process of walking the DOM tree and matching DOM elements to + * {@link ng.$compileProvider#methods_directive directives}. * - * The template function can then be used once to produce the view or as it is the case with - * {@link ng.directive:ngRepeat repeater} many-times, in which - * case each call results in a view that is a DOM clone of the original template. + *
+ * **Note:** This document is an in-depth reference of all directive options. + * For a gentle introduction to directives with examples of common use cases, + * see the {@link guide/directive directive guide}. + *
+ * + * ## Comprehensive Directive API + * + * There are many different options for a directive. + * + * The difference resides in the return value of the factory function. + * You can either return a "Directive Definition Object" (see below) that defines the directive properties, + * or just the `postLink` function (all other properties will have the default values). + * + *
+ * **Best Practice:** It's recommended to use the "directive definition object" form. + *
+ * + * Here's an example directive declared with a Directive Definition Object: + * + *
+ *   var myModule = angular.module(...);
+ *
+ *   myModule.directive('directiveName', function factory(injectables) {
+ *     var directiveDefinitionObject = {
+ *       priority: 0,
+ *       template: '
', // or // function(tElement, tAttrs) { ... }, + * // or + * // templateUrl: 'directive.html', // or // function(tElement, tAttrs) { ... }, + * replace: false, + * transclude: false, + * restrict: 'A', + * scope: false, + * controller: function($scope, $element, $attrs, $transclude, otherInjectables) { ... }, + * require: 'siblingDirectiveName', // or // ['^parentDirectiveName', '?optionalDirectiveName', '?^optionalParent'], + * compile: function compile(tElement, tAttrs, transclude) { + * return { + * pre: function preLink(scope, iElement, iAttrs, controller) { ... }, + * post: function postLink(scope, iElement, iAttrs, controller) { ... } + * } + * // or + * // return function postLink( ... ) { ... } + * }, + * // or + * // link: { + * // pre: function preLink(scope, iElement, iAttrs, controller) { ... }, + * // post: function postLink(scope, iElement, iAttrs, controller) { ... } + * // } + * // or + * // link: function postLink( ... ) { ... } + * }; + * return directiveDefinitionObject; + * }); + *
+ * + *
+ * **Note:** Any unspecified options will use the default value. You can see the default values below. + *
+ * + * Therefore the above can be simplified as: + * + *
+ *   var myModule = angular.module(...);
+ *
+ *   myModule.directive('directiveName', function factory(injectables) {
+ *     var directiveDefinitionObject = {
+ *       link: function postLink(scope, iElement, iAttrs) { ... }
+ *     };
+ *     return directiveDefinitionObject;
+ *     // or
+ *     // return function postLink(scope, iElement, iAttrs) { ... }
+ *   });
+ * 
+ * + * + * + * ### Directive Definition Object + * + * The directive definition object provides instructions to the {@link api/ng.$compile + * compiler}. The attributes are: + * + * #### `priority` + * When there are multiple directives defined on a single DOM element, sometimes it + * is necessary to specify the order in which the directives are applied. The `priority` is used + * to sort the directives before their `compile` functions get called. Priority is defined as a + * number. Directives with greater numerical `priority` are compiled first. The order of directives with + * the same priority is undefined. The default priority is `0`. + * + * #### `terminal` + * If set to true then the current `priority` will be the last set of directives + * which will execute (any directives at the current priority will still execute + * as the order of execution on same `priority` is undefined). + * + * #### `scope` + * **If set to `true`,** then a new scope will be created for this directive. If multiple directives on the + * same element request a new scope, only one new scope is created. The new scope rule does not + * apply for the root of the template since the root of the template always gets a new scope. + * + * **If set to `{}` (object hash),** then a new "isolate" scope is created. The 'isolate' scope differs from + * normal scope in that it does not prototypically inherit from the parent scope. This is useful + * when creating reusable components, which should not accidentally read or modify data in the + * parent scope. + * + * The 'isolate' scope takes an object hash which defines a set of local scope properties + * derived from the parent scope. These local properties are useful for aliasing values for + * templates. Locals definition is a hash of local scope property to its source: + * + * * `@` or `@attr` - bind a local scope property to the value of DOM attribute. The result is + * always a string since DOM attributes are strings. If no `attr` name is specified then the + * attribute name is assumed to be the same as the local name. + * Given `` and widget definition + * of `scope: { localName:'@myAttr' }`, then widget scope property `localName` will reflect + * the interpolated value of `hello {{name}}`. As the `name` attribute changes so will the + * `localName` property on the widget scope. The `name` is read from the parent scope (not + * component scope). + * + * * `=` or `=attr` - set up bi-directional binding between a local scope property and the + * parent scope property of name defined via the value of the `attr` attribute. If no `attr` + * name is specified then the attribute name is assumed to be the same as the local name. + * Given `` and widget definition of + * `scope: { localModel:'=myAttr' }`, then widget scope property `localModel` will reflect the + * value of `parentModel` on the parent scope. Any changes to `parentModel` will be reflected + * in `localModel` and any changes in `localModel` will reflect in `parentModel`. If the parent + * scope property doesn't exist, it will throw a NON_ASSIGNABLE_MODEL_EXPRESSION exception. You + * can avoid this behavior using `=?` or `=?attr` in order to flag the property as optional. + * + * * `&` or `&attr` - provides a way to execute an expression in the context of the parent scope. + * If no `attr` name is specified then the attribute name is assumed to be the same as the + * local name. Given `` and widget definition of + * `scope: { localFn:'&myAttr' }`, then isolate scope property `localFn` will point to + * a function wrapper for the `count = count + value` expression. Often it's desirable to + * pass data from the isolated scope via an expression and to the parent scope, this can be + * done by passing a map of local variable names and values into the expression wrapper fn. + * For example, if the expression is `increment(amount)` then we can specify the amount value + * by calling the `localFn` as `localFn({amount: 22})`. + * + * + * + * #### `controller` + * Controller constructor function. The controller is instantiated before the + * pre-linking phase and it is shared with other directives (see + * `require` attribute). This allows the directives to communicate with each other and augment + * each other's behavior. The controller is injectable (and supports bracket notation) with the following locals: + * + * * `$scope` - Current scope associated with the element + * * `$element` - Current element + * * `$attrs` - Current attributes object for the element + * * `$transclude` - A transclude linking function pre-bound to the correct transclusion scope: + * `function(cloneLinkingFn)`. + * + * + * #### `require` + * Require another directive and inject its controller as the fourth argument to the linking function. The + * `require` takes a string name (or array of strings) of the directive(s) to pass in. If an array is used, the + * injected argument will be an array in corresponding order. If no such directive can be + * found, or if the directive does not have a controller, then an error is raised. The name can be prefixed with: + * + * * (no prefix) - Locate the required controller on the current element. Throw an error if not found. + * * `?` - Attempt to locate the required controller or pass `null` to the `link` fn if not found. + * * `^` - Locate the required controller by searching the element's parents. Throw an error if not found. + * * `?^` - Attempt to locate the required controller by searching the element's parentsor pass `null` to the + * `link` fn if not found. + * + * + * #### `controllerAs` + * Controller alias at the directive scope. An alias for the controller so it + * can be referenced at the directive template. The directive needs to define a scope for this + * configuration to be used. Useful in the case when directive is used as component. + * + * + * #### `restrict` + * String of subset of `EACM` which restricts the directive to a specific directive + * declaration style. If omitted, the default (attributes only) is used. + * + * * `E` - Element name: `` + * * `A` - Attribute (default): `
` + * * `C` - Class: `
` + * * `M` - Comment: `` + * + * + * #### `template` + * replace the current element with the contents of the HTML. The replacement process + * migrates all of the attributes / classes from the old element to the new one. See the + * {@link guide/directive#creating-custom-directives_creating-directives_template-expanding-directive + * Directives Guide} for an example. + * + * You can specify `template` as a string representing the template or as a function which takes + * two arguments `tElement` and `tAttrs` (described in the `compile` function api below) and + * returns a string value representing the template. + * + * + * #### `templateUrl` + * Same as `template` but the template is loaded from the specified URL. Because + * the template loading is asynchronous the compilation/linking is suspended until the template + * is loaded. + * + * You can specify `templateUrl` as a string representing the URL or as a function which takes two + * arguments `tElement` and `tAttrs` (described in the `compile` function api below) and returns + * a string value representing the url. In either case, the template URL is passed through {@link + * api/ng.$sce#methods_getTrustedResourceUrl $sce.getTrustedResourceUrl}. + * + * + * #### `replace` + * specify where the template should be inserted. Defaults to `false`. + * + * * `true` - the template will replace the current element. + * * `false` - the template will replace the contents of the current element. + * + * + * #### `transclude` + * compile the content of the element and make it available to the directive. + * Typically used with {@link api/ng.directive:ngTransclude + * ngTransclude}. The advantage of transclusion is that the linking function receives a + * transclusion function which is pre-bound to the correct scope. In a typical setup the widget + * creates an `isolate` scope, but the transclusion is not a child, but a sibling of the `isolate` + * scope. This makes it possible for the widget to have private state, and the transclusion to + * be bound to the parent (pre-`isolate`) scope. + * + * * `true` - transclude the content of the directive. + * * `'element'` - transclude the whole element including any directives defined at lower priority. + * + * + * #### `compile` + * + *
+ *   function compile(tElement, tAttrs, transclude) { ... }
+ * 
+ * + * The compile function deals with transforming the template DOM. Since most directives do not do + * template transformation, it is not used often. Examples that require compile functions are + * directives that transform template DOM, such as {@link + * api/ng.directive:ngRepeat ngRepeat}, or load the contents + * asynchronously, such as {@link api/ngRoute.directive:ngView ngView}. The + * compile function takes the following arguments. + * + * * `tElement` - template element - The element where the directive has been declared. It is + * safe to do template transformation on the element and child elements only. + * + * * `tAttrs` - template attributes - Normalized list of attributes declared on this element shared + * between all directive compile functions. + * + * * `transclude` - A transclude linking function: `function(scope, cloneLinkingFn)`. + * + *
+ * **Note:** The template instance and the link instance may be different objects if the template has + * been cloned. For this reason it is **not** safe to do anything other than DOM transformations that + * apply to all cloned DOM nodes within the compile function. Specifically, DOM listener registration + * should be done in a linking function rather than in a compile function. + *
+ * + * A compile function can have a return value which can be either a function or an object. + * + * * returning a (post-link) function - is equivalent to registering the linking function via the + * `link` property of the config object when the compile function is empty. + * + * * returning an object with function(s) registered via `pre` and `post` properties - allows you to + * control when a linking function should be called during the linking phase. See info about + * pre-linking and post-linking functions below. + * + * + * #### `link` + * This property is used only if the `compile` property is not defined. + * + *
+ *   function link(scope, iElement, iAttrs, controller) { ... }
+ * 
+ * + * The link function is responsible for registering DOM listeners as well as updating the DOM. It is + * executed after the template has been cloned. This is where most of the directive logic will be + * put. + * + * * `scope` - {@link api/ng.$rootScope.Scope Scope} - The scope to be used by the + * directive for registering {@link api/ng.$rootScope.Scope#methods_$watch watches}. + * + * * `iElement` - instance element - The element where the directive is to be used. It is safe to + * manipulate the children of the element only in `postLink` function since the children have + * already been linked. + * + * * `iAttrs` - instance attributes - Normalized list of attributes declared on this element shared + * between all directive linking functions. + * + * * `controller` - a controller instance - A controller instance if at least one directive on the + * element defines a controller. The controller is shared among all the directives, which allows + * the directives to use the controllers as a communication channel. + * + * + * + * #### Pre-linking function + * + * Executed before the child elements are linked. Not safe to do DOM transformation since the + * compiler linking function will fail to locate the correct elements for linking. + * + * #### Post-linking function + * + * Executed after the child elements are linked. It is safe to do DOM transformation in the post-linking function. + * + * + * ### Attributes + * + * The {@link api/ng.$compile.directive.Attributes Attributes} object - passed as a parameter in the + * `link()` or `compile()` functions. It has a variety of uses. + * + * accessing *Normalized attribute names:* + * Directives like 'ngBind' can be expressed in many ways: 'ng:bind', `data-ng-bind`, or 'x-ng-bind'. + * the attributes object allows for normalized access to + * the attributes. + * + * * *Directive inter-communication:* All directives share the same instance of the attributes + * object which allows the directives to use the attributes object as inter directive + * communication. + * + * * *Supports interpolation:* Interpolation attributes are assigned to the attribute object + * allowing other directives to read the interpolated value. + * + * * *Observing interpolated attributes:* Use `$observe` to observe the value changes of attributes + * that contain interpolation (e.g. `src="{{bar}}"`). Not only is this very efficient but it's also + * the only way to easily get the actual value because during the linking phase the interpolation + * hasn't been evaluated yet and so the value is at this time set to `undefined`. + * + *
+ * function linkingFn(scope, elm, attrs, ctrl) {
+ *   // get the attribute value
+ *   console.log(attrs.ngModel);
+ *
+ *   // change the attribute
+ *   attrs.$set('ngModel', 'new value');
+ *
+ *   // observe changes to interpolated attribute
+ *   attrs.$observe('ngModel', function(value) {
+ *     console.log('ngModel has changed value to ' + value);
+ *   });
+ * }
+ * 
+ * + * Below is an example using `$compileProvider`. + * + *
+ * **Note**: Typically directives are registered with `module.directive`. The example below is + * to illustrate how `$compile` works. + *
*