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A detailed explanation of getting started with Jade in Node.js

亚连Original: 2018-06-11 14:30:581263browse

This article mainly introduces the detailed introduction to the Node.js template engine Jade. Jade is a template engine for Node.js. Now I will share it with you and give you a reference.

Jade is a template engine for Node.js. It draws on many aspects of Haml, so its syntax is similar to Haml. Moreover, Jade also supports spaces.

1. Tags

In Jade, any text at the beginning of a line is interpreted as an HTML tag by default. And you only need to write the opening tag-note: no need to add "a8093152e673feb7aba1828c43532094". Because Jade will render the closing and opening tags for us. For example:

body 
  p 
    h1 Jade是Node.js的一个模板引擎
    p  它借鉴了Haml的很多地方，所以语法上和Haml比较相近。
  p 
    footer © Pandora

The HTML code finally rendered by the Jade template above is:

<body>
  <p>
    <h1> Jade是Node.js的一个模板引擎</h1>
    <p>它借鉴了Haml的很多地方，所以语法上和Haml比较相近。</p>
  </p>
  <p>
    <footer>© Pandora</footer>
  </p>
</body>

Note: If no tag name is written, the default is the p tag.

2. Variables/data

The data passed to the Jade template is called locals. Use the equal sign "=" to output the value of a variable.

(locals):

{
  title: "Express.js Guide",
  body: "The Comprehensive Book on Express.js"
}

Jade code:

h1= title
p= body

Rendered output HTML:

<h1>Express.js Guide</h1>
<p>The Comprehensive Book on Express.js</p>

3. Read variables

Reading the value of a variable in Jade is achieved through #{name}. For example:

- var title = "Node"

p I love #{title}

The value of the variable is processed when the template is compiled, so do not use it in executable JavaScript(-).

4. Attributes

The attributes follow the label and are enclosed by "()", and multiple attributes are separated by ",". For example: body (name1 = “value1”, name2 = “value2”).

p(id="content", class=&#39;main&#39;)
  a(href=&#39;http://csdn.net&#39;, title=&#39;csdn主页&#39;， target=&#39;_blank&#39;) CSDN:中国软件联盟
  form(action="/login")
    button(type="submit", value="提交")

Output:

<p id="content" class=&#39;main&#39;>
  <a href=&#39;http://csdn.net&#39; title=&#39;csdn主页&#39; target=&#39;_blank&#39;> CSDN:中国软件联盟</a>
  <form action="/login">
    <button type="submit" value="提交">
  </form>
</p>

Dynamic attributes:

Dynamic attributes means that the value of the attribute is dynamic, that is, a variable is used to represent the value of the attribute. . The symbol "|" can write HTML node content in a new line. For example:

a(href=url, data-active=isActive)
label
  input(type="checkbox", checked=isChecked)
  | yes / no

The data provided to the above template:

{
  url: "/logout",
  isActive: true,
  isChecked: false
}

The HTML output after final rendering:

<a href="" data-active=" rel="external nofollow" data-active"></a>
<label>
  <input type="checkbox" />yes / no
</label>

Note: The attribute value of false is used when outputting HTML code will be ignored; when no attribute value is passed in, it will default to true.

5. Literal

To save trouble, you can write the class directly after the tag name name and ID name. For example:

p#content
  p.lead.center
    | Pandora_galen
    #side-bar.pull-right // 没有标签名，默认为“p”
    span.contact.span4
      a(href="/contact" rel="external nofollow" rel="external nofollow" ) contact me

Rendered output HTML:

<p id="content">
  <p class="lead center">
  Pandora_galen
  <p id="side-bar" class="pull-right"></p>
  <span class="contact span4">
    <a href="/contact" rel="external nofollow" rel="external nofollow" > contact me </a>
  </span>
</p>

6, text

Use the "|" symbol to output the original text.

p 
  | 我两年前开始学习前端
  | 在此之间，我学过了html, jQuery, JavaScript, Python， Css3, HTML5, Bootstrap, D3.js, SVG...而现在我在学Node。并且我已经深深的爱上了前端。

7. Script and Style blocks

Use the "." symbol to create in HTML

script.
  console.log("Hello world!");
  setTiemout(function() {
    window.location.href = "http://csdn.net"
  }, 1000);

  console.log("Good bye!");

Generated code:

<script>
  console.log("Hello world!");
  setTiemout(function() {
    window.location.href = "http://csdn.net"
  }, 1000);

  console.log("Good bye!");
</script>

Similarly, style. generates c9ccee2e6ea535a969eb3f532ad9fe89531ac245ce3e4fe3d50054a55f265927.

8. JavaScript code

Use -, = or! =These three symbols are used to write executable JS code in Jade that can manipulate the output. This is useful when outputting HTML elements and injecting JavaScript. However, you must be careful to avoid cross-site scripting (XSS) attacks when doing this.

For example, you can use it! =Define an array and output tag data:

- var arr = [&#39;<a>&#39;, &#39;<b>&#39;, &#39;<c>&#39;]
ul
  -for (var i = 0; i < arr.length; i++)
    li
      span= i
      span!= "unescaped:" + arr[i] + "vs."
      span= "escaped:" + arr[i]

The generated code is as follows:

<ul>
  <li><span>0</span><span>unescaped: <a>vs. </span><span>escaped: <a></span></li>
  <li><span>1</span><span>unescaped: <b>vs. </span><span>escaped: <b></span></li>
  <li><span>2</span><span>unescaped: <c>vs. </span><span>escaped: <c></span></li>
</ul>

One of the main differences between the template engine Jade and Handlebars is: Jade allows almost all JavaScript to be written in the code ; However, Handlebars limit developers to a small number of built-in and custom helpers.

9. Comments

There are two types of Jade comments:

f35d6e602fd7d0f0edfa6f7d103c1b57. Output to the page - "//"
2cc198a1d5eb0d3eb508d858c9f5cbdb. Not output to the page - "//-"

// 普通注释，会输出到渲染后生成的HTML页面
p Hello Jade content

//- 特殊注释，不会输出到HTML页面
p (id="footer") copyright 2016

Output:

<!-- 普通注释，会输出到渲染后生成的HTML页面 -->
<p> Hello Jade content </p>

<p id="footer">copyright 2016</p>

10, if statement

Add a prefix - to the if statement, so that you can write standard JavaScript code; you can also use it without the prefix or parentheses, of course the latter is more concise.

- var user = {}
- user.admin = Math.random() > 0.5

if user.admin
  button(class = "launch") Launch Spacecraft
else 
  button(class = "login") Log in

In addition, there is unless, which is equivalent to no or! .

Note: There is no semicolon ";" at the end of each line of code

11. Each statement

Iteration in Jade is very simple. Just use the each statement.

- var language = [&#39;JavaScript&#39;, &#39;Node&#39;, &#39;Python&#39;, &#39;Java&#39;]
p
  each value, index in language
    p= index + "," + value

Output:

<p>
  <p>0. JavaScript</p>
  <p>1. Node</p>
  <p>2. Python</p>
  <p>3. Java</p>
</p>

Example 2:

- var language = [&#39;JavaScript&#39;: -1, &#39;Node&#39;: 2, &#39;Python&#39;: 3, &#39;Java&#39;: 1]

p 
  each value, key in languages
    p= key + ":" + value

Output:

<p>
  <p>JavaScript: -1</p>
  <p>Node: 2</p>
  <p>Python: 3</p>
  <p>Java: 1</p>
</p>

12, Filter

The function of the filter is: Use another language to write a text block;

p
  :markdown
    # practical Node.js
    [This book](http://csdn.net) really helps to grasp many coponents needed for modern-day web development.

Note: To use the Markdown filter, you need to install the Markdown module, as well as the Marked and Markdown NPM packages.

13、case

- var coins = Math.round(Math.random() * 10)

case coins
  when 0
    p You have no money
  when 1
    p You have a coin
  default
    p You have #{coins} coins!

14、Function mixin

If you have used sass or compass mixin, you are sure It won't be unfamiliar, and the usage of mixin in Jade is basically the same as them.

Declaration syntax: mixin name(param, param2, …….)

Call: name(data)

mixin row(items)
  tr
    each item, index in items
      td= item

mixin table(tableData)
  table
    each row, index in tableData
      +row(row)

- var node = [{name: "express"}, {name: "Jade"}, {name: "Handlebars"}]
+table(node)

- var js = [{name: &#39;backbone&#39;}, {name: &#39;angular&#39;}, {name: "emberJS"}]
+table(js)

Output:

<table>
  <tr>
    <td>express</td>
  </tr>
  <tr>
    <td>Jade</td>
  </tr>
  <tr>
    <td>Handlebars</td>
  </tr>
</table>

<table>
  <tr>
    <td>backbone</td>
  </tr>
  <tr>
    <td>angular</td>
  </tr>
  <tr>
    <td>emberJS</td>
  </tr>
</table>

15. include

include is very similar to introducing JS and CSS external files. It's a top-down approach: in the main file that includes other files, we decide what to use. The main file will be processed first (data locals can be defined in the main file), and then the sub-files included in the main file will be processed (the sub-files can use data locals defined in the main file);

To include a Jade template, use include /path/filename.

For example, in file A:

include ./includes/header

Note: There is no need to add double quotes or single quotes to the template name and path here. .

Another example, start searching from the parent directory:

include ../includes/footer

Note: You cannot use variables in file names and file paths, because includes/partials are processed at compile time, not at execution time .

对于使用Sass、Compass又或者Less的人这些事再熟悉不过的了。

16、extend

extend与include“唱对台戏”，正好相反，extend是一种自底向上的方法。它所包含的文件决定它要替换主文件中哪那一部分。

使用格式： extend filename 和 block blockname;

示例-1：在文件file_a里：

block header
  p some default text
block content
  p loading...
block footer
  p copyright

示例-2：在文件file_b里：

extend file_a
block header
  p very specific text
block content
  .main-content

上面是我整理给大家的，希望今后会对大家有帮助。

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