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diff --git a/posts/index.md b/posts/index.md index 372b7d0..6abb796 100644 --- a/posts/index.md +++ b/posts/index.md @@ -19,14 +19,11 @@ Handlebars 兼容 Mustache 模板。你可以在 Handlebars 中直接使用 Must <a class="download" href="http://builds.handlebarsjs.com.s3.amazonaws.com/handlebars-v3.0.1.js">Download: 3.0.1</a> <a class="download-runtime" href="http://builds.handlebarsjs.com.s3.amazonaws.com/handlebars.runtime-v3.0.1.js">Download: runtime-3.0.1</a> -Getting Started +快速入门 --------------- -<!-- Start .contents--> -<!---<dic class="contents">--> - -<!---<div class="bullet">--> - +<!---<dic class="contents">--><!-- Start .contents--> + Handlebars 模板看起来很像 HTML ，Handlebars 表达式嵌入在 HTML 中。 ```html @@ -37,15 +34,12 @@ Handlebars 模板看起来很像 HTML ，Handlebars 表达式嵌入在 HTML 中 </div> </div> ``` -Handlebars 表达式以 `{{`属性名`}}` 的方式插入数据。 - -<a href="expressions.md" class="more-info">了解更多：表达式</a> -<!---</div>--> +Handlebars 表达式以 `{{`属性名`}}` 的方式插入数据。 -<a name="index-1.html"></a> +<a href="expressions.md" class="more-info">高级教程：表达式</a> -<!---<div class="bullet">--> +--------------------- 你可以在 HTML 中使用 `<script>` 标签存放模板 @@ -60,9 +54,7 @@ Handlebars 表达式以 `{{`属性名`}}` 的方式插入数据。 </script> ``` -<!---</div>--> - -<!---<div class="bullet">--> +--------------------- 在 JavaScript 中获取 `<scrit>` 中的模板并编译模板 @@ -71,13 +63,351 @@ var source = $("#entry-template").html(); var template = Handlebars.compile(source); ``` -[示例](demo/index-1.html) +<!---<div class="translator">--> +建议初学者跳过预编译章节 +<!---</div>--> 还可以预编译你的模板。预编译后的模板只需使用 [handlebars.runtime.js](http://builds.handlebarsjs.com.s3.amazonaws.com/handlebars.runtime-v3.0.0.js) 渲染，这样可以提高性能并减少文件大小。在移动设备中这样做非常有意义（因为移动设备的性能和网络状态都没有PC好）。 -<a href="#" class="more-info">了解更多：预编译</a> -<!---</div>--> +<a href="precompilation.md" class="more-info">高级教程：预编译</a> -<!---</div>--> -<!-- End .contents-->
\ No newline at end of file +--------------------- + +传入数据，执行 Handlebars 返回 渲染后的 HTML。 + +```js +var source = $("#entry-template").html(); +var template = Handlebars.compile(source); + +var context = {title: "My New Post", body: "This is my first post!"}; +var html = template(context); +``` + +渲染结果 + +```html +<div class="entry"> + <h1>My New Post</h1> + <div class="body"> + This is my first post! + </div> +</div> +``` + +[示例](demo/execution-1.html) + +<a href="execution.md" class="more-info">高级教程: 执行</a> + +HTML 转义 +------------- + +遇到 HTML标签时 Handlebars 会返回转义后的 HTML，如果你不希望被转义，可以使用 `{{{` + +```html +<div class="entry"> + <h1>{{title}}</h1> + <div class="body"> + {{{body}}} + </div> +</div> +``` + +渲染数据： + +```js +{ + title: "All about <p> Tags", + body: "<p>This is a post about <p> tags</p>" +} +``` + +渲染结果： + +```html +<div class="entry"> + <h1>All About <p> Tags</h1> + <div class="body"> + <p>This is a post about <p> tags</p> + </div> +</div> +``` + +<a href="#SafeString" name="SafeString"></a> + +Handlebars 不会转义 `Handlebars.SafeString` 。如果你自定义了一个 helper 返回 HTML 代码，你需要返回 `new Handlebars.SafeString(result)` ，那么你需要手动对内容进行转义 + +```js +Handlebars.registerHelper('link', function(text, url) { + text = Handlebars.Utils.escapeExpression(text); + url = Handlebars.Utils.escapeExpression(url); + + var result = '<a href="' + url + '">' + text + '</a>'; + + return new Handlebars.SafeString(result); +}); +``` + +`new Handlebars.SafeString()` 会标识传入参数是“安全的”，所以即使你不使用 `{{{` 。Handlebars 也不会转义。 + +[示例](demo/SafeString.md) + + +块表达式 +------- + +块表达式允许你定义helper，用不同的数据上下文（context）调用一段模板。下面我们定义一个生成列表的helper： + +快表达式允许你自定义 helper，使用当前传入参数作为上下文调用模板。 + +创建一个用于生产列表的快表达式 + +``` +{{#list people}}{{firstName}} {{lastName}}{{/list}} +``` + +渲染数据如下所示： + +```js +{ + people: [ + {firstName: "Yehuda", lastName: "Katz"}, + {firstName: "Carl", lastName: "Lerche"}, + {firstName: "Alan", lastName: "Johnson"} + ] +} +``` + +we would create a helper named `list` to generate our HTML list. The helper receives the `people` as its first parameter, and an options hash as its second parameter. The options hash contains a property named `fn`, which you can invoke with a context just as you would invoke a normal Handlebars template. + +```js +Handlebars.registerHelper('list', function(items, options) { + var out = "<ul>"; + + for(var i=0, l=items.length; i<l; i++) { + out = out + "<li>" + options.fn(items[i]) + "</li>"; + } + + return out + "</ul>"; +}); +``` + +When executed, the template will render: + +```html +<ul> + <li>Yehuda Katz</li> + <li>Carl Lerche</li> + <li>Alan Johnson</li> +</ul> +``` + +Block helpers have more features, such as the ability to create an else section (used, for instance, by the built-in if helper). + +Since the contents of a block helper are escaped when you call `options.fn(context)`, Handlebars does not escape the results of a block helper. If it did, inner content would be double-escaped! + +<a href="block_helpers.md" class="more-info">Learn More: Block Helpers</a> + +Handlebars Paths +---------------- + +Handlebars supports simple paths, just like Mustache. + +```html +<p>{{name}}</p> +``` + +Handlebars also supports nested paths, making it possible to look up properties nested below the current context. + +```html +<div class="entry"> + <h1>{{title}}</h1> + <h2>By {{author.name}}</h2> + + <div class="body"> + {{body}} + </div> +</div> +``` + +That template works with this context + + +``` +var context = { + title: "My First Blog Post!", + author: { + id: 47, + name: "Yehuda Katz" + }, + body: "My first post. Wheeeee!" +}; +``` + +This makes it possible to use Handlebars templates with more raw JSON objects. + +Nested handlebars paths can also include `../` segments, which evaluate their paths against a parent context. + + + +```html +<h1>Comments</h1> + +<div id="comments"> + {{#each comments}} + <h2><a href="/posts/{{../permalink}}#{{id}}">{{title}}</a></h2> + <div>{{body}}</div> + {{/each}} +</div> +``` + +Even though the link is printed while in the context of a comment, it can still go back to the main context (the post) to retrieve its permalink. + +The `../` path segment references the parent template scope, not one level up in the context. This is because block helpers can invoke a block with any context, so the notion of "one level up" isn't particularly meaningful except as a reference to the parent template scope. + + + +Handlebars also allows for name conflict resolution between helpers and data fields via a this reference: + +```html +<p>{{./name}} or {{this/name}} or {{this.name}}</p> +``` + +Any of the above would cause the `name` field on the current context to be used rather than a helper of the same name. + + +Template comments with {{!-- --}} or {{! }}. +--------------------------------------------- + +You can use comments in your handlebars code just as you would in your code. Since there is generally some level of logic, this is a good practice. + +```html +<div class="entry"> + {{!-- only output this author names if an author exists --}} + {{#if author}} + <h1>{{firstName}} {{lastName}}</h1> + {{/if}} +</div> +``` + +The comments will not be in the resulting output. If you'd like the comments to show up. Just use html comments, and they will be output. + +```html +<div class="entry"> + {{! This comment will not be in the output }} + <!-- This comment will be in the output --> +</div> +``` + +Any comments that must contain `}}` or other handlebars tokens should use the `{{!-- --}}` syntax. + +Helpers +------- + +Handlebars helpers can be accessed from any context in a template. You can register a helper with the `Handlebars.registerHelper` method. + +```html +<div class="post"> + <h1>By {{fullName author}}</h1> + <div class="body">{{body}}</div> + <h1>Comments</h1> + {{#each comments}} + <h2>By {{fullName author}}</h2> + <div class="body">{{body}}</div> + {{/each}} +</div> +``` + + +when using this context and helpers: + +```js +var context = { + author: {firstName: "Alan", lastName: "Johnson"}, + body: "I Love Handlebars", + comments: [{ + author: {firstName: "Yehuda", lastName: "Katz"}, + body: "Me too!" + }] +}; + +Handlebars.registerHelper('fullName', function(person) { + return person.firstName + " " + person.lastName; +}); +``` + +results in: + +```html +<div class="post"> + <h1>By Alan Johnson</h1> + <div class="body">I Love Handlebars</div> + <h1>Comments</h1> + <h2>By Yehuda Katz</h2> + <div class="body">Me Too!</div> +</div> +``` + + +Helpers receive the current context as the `this` context of the function. + +```html +<ul> + {{#each items}} + <li>{{agree_button}}</li> + {{/each}} +</ul> +``` + +when using this context and helpers: + +```js +var context = { + items: [ + {name: "Handlebars", emotion: "love"}, + {name: "Mustache", emotion: "enjoy"}, + {name: "Ember", emotion: "want to learn"} + ] +}; + +Handlebars.registerHelper('agree_button', function() { + var emotion = Handlebars.escapeExpression(this.emotion), + name = Handlebars.escapeExpression(this.name); + + return new Handlebars.SafeString( + "<button>I agree. I " + emotion + " " + name + "</button>" + ); +}); +``` + +results in: + +```html +<ul> + <li><button>I agree. I love Handlebars</button></li> + <li><button>I agree. I enjoy Mustache</button></li> + <li><button>I agree. I want to learn Ember</button></li> +</ul> +``` + +If your helper returns HTML that you do not want escaped, make sure to return a new Handlebars.SafeString. + + + +Built-In Helpers +---------------- + +Handlebars offers a variety of built-in helpers such as the if conditional and each iterator. + +<a href="builtin_helpers.md" class="more-info">Learn More: Built-In Helpers</a> + + +API Reference +------------- + +Handlebars offers a variety of APIs and utility methods for applications and helpers. + +<a href="reference.md" class="more-info">Learn More: API Reference</a> + + +<!---</div>--><!-- End .contents
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