https://github.com/grantila/node-property
Getter-setter wrapper with notification support
https://github.com/grantila/node-property
Last synced: 7 months ago
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Getter-setter wrapper with notification support
- Host: GitHub
- URL: https://github.com/grantila/node-property
- Owner: grantila
- License: mit
- Created: 2016-05-12T13:37:20.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2016-05-13T07:50:45.000Z (over 9 years ago)
- Last Synced: 2024-12-17T01:34:23.980Z (10 months ago)
- Language: JavaScript
- Size: 3.91 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# property
*property* is a getter-setter wrapper object, which wraps any value. The value is read by calling the property without an argument, and is set by calling the property with the value as argument.
`property` objects emit events to notify when they are changed.
The idea behind `property` comes from mithril's `m.prop()` feature, which is useful not only in mithril, but together with other frameworks, e.g. React.
## Usage
```js
var property = require( 'property' );
var prop = property( ); // Creates a property
prop( ); // Returns undefined
prop( 5 ); // Sets value 5
prop( ); // Returns 5
prop( "x" ); // Sets value "x"
prop( ); // Returns "x"
var prop2 = property( "test" ); // Creates a property with initial value "test"
prop( ); // Returns "test"
var prop3 = property( 1 );
prop3.emitter.on( 'data', data => console.log( data ) );
prop3( prop3( ) + 1 ); // Reads value, adds one, then sets value
// console.log: 2
```
Since event emitters are used, if you add a listener, you must remember to remove the listener when appropriate, or your application will leak memory. This applies to all usages of event emitters, `property` is no exception.
### Manually triggering change events
To trigger an event to be sent, use the `notify( )` function. This can be useful if you want to bypass built-in getter-setter notification by modifying internal properties in the object.
```js
var prop = property( { } );
// ...
prop( )[ "hello" ] = "world"; // Modifies the object, but will not notify
prop.notify( ); // Manually notify
```
## Masquerading
### Property objects fit in JSON objects
A property object is auto-convertible to JSON.
```js
var prop = property( { a: 1 } );
JSON.stringify( { p: prop } ); // -> { p: { a: 1 } }
```
### Property objects forward `toString` and `valueOf`.
A property object has a `toString` and a `valueOf` function which forwards to the underlying value.
```js
var prop = property( 1 );
1 + prop; // -> 2
var prop2 = property( "world" );
"hello " + prop2; // -> "hello world"
```