forked from zhurui/management
172 lines
6.0 KiB
Markdown
172 lines
6.0 KiB
Markdown
# amdefine
|
|
|
|
A module that can be used to implement AMD's define() in Node. This allows you
|
|
to code to the AMD API and have the module work in node programs without
|
|
requiring those other programs to use AMD.
|
|
|
|
## Usage
|
|
|
|
**1)** Update your package.json to indicate amdefine as a dependency:
|
|
|
|
```javascript
|
|
"dependencies": {
|
|
"amdefine": ">=0.1.0"
|
|
}
|
|
```
|
|
|
|
Then run `npm install` to get amdefine into your project.
|
|
|
|
**2)** At the top of each module that uses define(), place this code:
|
|
|
|
```javascript
|
|
if (typeof define !== 'function') { var define = require('amdefine')(module) }
|
|
```
|
|
|
|
**Only use these snippets** when loading amdefine. If you preserve the basic structure,
|
|
with the braces, it will be stripped out when using the [RequireJS optimizer](#optimizer).
|
|
|
|
You can add spaces, line breaks and even require amdefine with a local path, but
|
|
keep the rest of the structure to get the stripping behavior.
|
|
|
|
As you may know, because `if` statements in JavaScript don't have their own scope, the var
|
|
declaration in the above snippet is made whether the `if` expression is truthy or not. If
|
|
RequireJS is loaded then the declaration is superfluous because `define` is already already
|
|
declared in the same scope in RequireJS. Fortunately JavaScript handles multiple `var`
|
|
declarations of the same variable in the same scope gracefully.
|
|
|
|
If you want to deliver amdefine.js with your code rather than specifying it as a dependency
|
|
with npm, then just download the latest release and refer to it using a relative path:
|
|
|
|
[Latest Version](https://github.com/jrburke/amdefine/raw/latest/amdefine.js)
|
|
|
|
### amdefine/intercept
|
|
|
|
Consider this very experimental.
|
|
|
|
Instead of pasting the piece of text for the amdefine setup of a `define`
|
|
variable in each module you create or consume, you can use `amdefine/intercept`
|
|
instead. It will automatically insert the above snippet in each .js file loaded
|
|
by Node.
|
|
|
|
**Warning**: you should only use this if you are creating an application that
|
|
is consuming AMD style defined()'d modules that are distributed via npm and want
|
|
to run that code in Node.
|
|
|
|
For library code where you are not sure if it will be used by others in Node or
|
|
in the browser, then explicitly depending on amdefine and placing the code
|
|
snippet above is suggested path, instead of using `amdefine/intercept`. The
|
|
intercept module affects all .js files loaded in the Node app, and it is
|
|
inconsiderate to modify global state like that unless you are also controlling
|
|
the top level app.
|
|
|
|
#### Why distribute AMD-style modules via npm?
|
|
|
|
npm has a lot of weaknesses for front-end use (installed layout is not great,
|
|
should have better support for the `baseUrl + moduleID + '.js' style of loading,
|
|
single file JS installs), but some people want a JS package manager and are
|
|
willing to live with those constraints. If that is you, but still want to author
|
|
in AMD style modules to get dynamic require([]), better direct source usage and
|
|
powerful loader plugin support in the browser, then this tool can help.
|
|
|
|
#### amdefine/intercept usage
|
|
|
|
Just require it in your top level app module (for example index.js, server.js):
|
|
|
|
```javascript
|
|
require('amdefine/intercept');
|
|
```
|
|
|
|
The module does not return a value, so no need to assign the result to a local
|
|
variable.
|
|
|
|
Then just require() code as you normally would with Node's require(). Any .js
|
|
loaded after the intercept require will have the amdefine check injected in
|
|
the .js source as it is loaded. It does not modify the source on disk, just
|
|
prepends some content to the text of the module as it is loaded by Node.
|
|
|
|
#### How amdefine/intercept works
|
|
|
|
It overrides the `Module._extensions['.js']` in Node to automatically prepend
|
|
the amdefine snippet above. So, it will affect any .js file loaded by your
|
|
app.
|
|
|
|
## define() usage
|
|
|
|
It is best if you use the anonymous forms of define() in your module:
|
|
|
|
```javascript
|
|
define(function (require) {
|
|
var dependency = require('dependency');
|
|
});
|
|
```
|
|
|
|
or
|
|
|
|
```javascript
|
|
define(['dependency'], function (dependency) {
|
|
|
|
});
|
|
```
|
|
|
|
## RequireJS optimizer integration. <a name="optimizer"></name>
|
|
|
|
Version 1.0.3 of the [RequireJS optimizer](http://requirejs.org/docs/optimization.html)
|
|
will have support for stripping the `if (typeof define !== 'function')` check
|
|
mentioned above, so you can include this snippet for code that runs in the
|
|
browser, but avoid taking the cost of the if() statement once the code is
|
|
optimized for deployment.
|
|
|
|
## Node 0.4 Support
|
|
|
|
If you want to support Node 0.4, then add `require` as the second parameter to amdefine:
|
|
|
|
```javascript
|
|
//Only if you want Node 0.4. If using 0.5 or later, use the above snippet.
|
|
if (typeof define !== 'function') { var define = require('amdefine')(module, require) }
|
|
```
|
|
|
|
## Limitations
|
|
|
|
### Synchronous vs Asynchronous
|
|
|
|
amdefine creates a define() function that is callable by your code. It will
|
|
execute and trace dependencies and call the factory function *synchronously*,
|
|
to keep the behavior in line with Node's synchronous dependency tracing.
|
|
|
|
The exception: calling AMD's callback-style require() from inside a factory
|
|
function. The require callback is called on process.nextTick():
|
|
|
|
```javascript
|
|
define(function (require) {
|
|
require(['a'], function(a) {
|
|
//'a' is loaded synchronously, but
|
|
//this callback is called on process.nextTick().
|
|
});
|
|
});
|
|
```
|
|
|
|
### Loader Plugins
|
|
|
|
Loader plugins are supported as long as they call their load() callbacks
|
|
synchronously. So ones that do network requests will not work. However plugins
|
|
like [text](http://requirejs.org/docs/api.html#text) can load text files locally.
|
|
|
|
The plugin API's `load.fromText()` is **not supported** in amdefine, so this means
|
|
transpiler plugins like the [CoffeeScript loader plugin](https://github.com/jrburke/require-cs)
|
|
will not work. This may be fixable, but it is a bit complex, and I do not have
|
|
enough node-fu to figure it out yet. See the source for amdefine.js if you want
|
|
to get an idea of the issues involved.
|
|
|
|
## Tests
|
|
|
|
To run the tests, cd to **tests** and run:
|
|
|
|
```
|
|
node all.js
|
|
node all-intercept.js
|
|
```
|
|
|
|
## License
|
|
|
|
New BSD and MIT. Check the LICENSE file for all the details.
|