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Merge pull request #88 from vjeux/jsx_pitfall

Adding JSX pitfalls section in the docs
main
petehunt 12 years ago
parent
commit
2a77affe0c
  1. 7
      _includes/nav_docs.html
  2. 1
      docs/api.md
  3. 95
      docs/jsx-is-not-html.md

7
_includes/nav_docs.html

@ -21,4 +21,11 @@
<li><a href="/react/docs/api.html"{% if page.id == 'docs-api' %} class="active"{% endif %}>API</a></li>
</ul>
</div>
<div class="nav-docs-section">
<h3>Appendix</h3>
<ul>
<li><a href="/react/docs/jsx-is-not-html.html"{% if page.id == 'docs-jsx-is-not-html' %} class="active"{% endif %}>JSX is not HTML</a></li>
</ul>
</div>
</div>

1
docs/api.md

@ -3,6 +3,7 @@ id: docs-api
title: React API
layout: docs
prev: mixins.html
next: jsx-is-not-html.html
---
## React

95
docs/jsx-is-not-html.md

@ -0,0 +1,95 @@
---
id: docs-jsx-is-not-html
title: JSX is not HTML
description: Differences between JSX and HTML.
layout: docs
prev: api.html
---
JSX looks like HTML but there are some important differences you may run into.
## Whitespace removal
JSX doesn't follow the same whitespace elimination rules as HTML. JSX removes all the whitespaces between two curly braces expressions. If you want to have a white space, a work-around is to add `{' '}`.
```javascript
<div>{this.props.name} {' '} {this.props.surname}</div>
```
This behavior is still being debated. Follow [Issue #65](https://github.com/facebook/react/issues/65) to be updated on the situation.
## HTML Entities
You can insert HTML entities within literal text in JSX:
```javascript
<div>First &middot; Second</div>
```
If you want to display an HTML entity within a dynamic content, you will run into double escaping issues as React escapes all the strings you are displaying in order to prevent a wide range of XSS attacks by default.
```javascript
// Bad: It displays "First &middot; Second"
<div>{'First &middot; Second'}</div>
```
There are various ways to work-around this issue. The easiest one is to write unicode character directly in Javascript. You've got to make sure that the file is saved as UTF-8 and that the propers UTF-8 directives are set so the browser will display it correctly.
```javascript
<div>{'First · Second'}</div>
```
A safer alternative is to find the <a href="http://www.fileformat.info/info/unicode/char/b7/index.htm">unicode number corresponding to the entity</a> and use it inside of a Javascript string.
```javascript
<div>{'First \u00b7 Second'}</div>
<div>{'First ' + String.fromCharCode(183) + ' Second'}</div>
```
You can use mixed arrays with strings and JSX elements.
```javascript
<div>{['First ', <span>&middot;</span>, ' Second']}</div>
```
In last resort, you always have the ability to insert raw HTML inside of the div.
```javascript
<div dangerouslySetInnerHTML={{'{{'}}__html: 'First &middot; Second'}} />
```
## Comments
JSX supports both single-line and multi-lines Javascript comments within a tag declaration:
```javascript
<div // This is a single line comment:
/*
And a multiline
comment
*/
/>
```
As of React 0.3, there is no good way to insert comments within the children section. [Issue #82](https://github.com/facebook/react/issues/82) is tracking progress to enable the following way to write comments:
```javascript
// Note: The following is not implemented yet!
<div>
{/* This is a comment */}
</div>
```
## Custom HTML attributes
If you pass properties to native HTML elements that do not exist in the HTML specification, React will not render them. If you want to use a custom attribute, you should prefix it with `data-`.
```javascript
<div data-custom-attribute="foo" />
```
[Web Accessibility](http://www.w3.org/WAI/intro/aria) attributes starting with `aria-` will be rendered properly.
```javascript
<div aria-hidden={true} />
```
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