set-aside

Using a side storage (WeakMap) to create property setter hooks on an object.

API

setAside.sideStore(obj)

Gives you the "side storage" object for an object. Uses WeakMap where available, or a non-enumerable property containing the side storage object where not.

setAside.sideSet(obj, key, {before, after})

Create a get/set property named key on the object using defineProperty. If the property was already a get/set property, it will chain onto the current getter and setter. If passed before and after can be functions with the argument list (newValue, oldValue, thisArg). The thisArg is passed in to make using arrows here a bit easier if you want.

setAside.beforeSet(obj, key, hook)

setAside.afterSet(obj, key, hook)

The hook should look like function( newValue, oldValue, thisArg ) {}. Just an alias for sideSet

Examples

class Foo {
  triggerRender() { console.log('trigger!'); }
}
 
setAside.afterSet(Foo.prototype, 'data', function() { this.triggerRender(); });
 
new Foo().data = 'foo'; // logs 'trigger!'