construe

Object.defineProperty wrapper with nice description methods

Installation

node.js

npm install construe

browser

bower install construe

<script type="text/javascript" href="/bower_components/eventEmitter/EventEmitter.js"/>
<script type="text/javascript" href="/bower_components/construe/index.js"/>

Share nodejs module with the browser

If you use express you can use confinience method to share this node module with the browser: This route will merge all construe dependencies into one file.

app.get('/construe.js', construe.expressRoute);

Documentation

construe method basically does what Object.defineProperty / Object .defineProperties does.

If we specify 2 arguments then Object.defineProperties method is called.

If we specify 3 arguments then Object.defineProperty method is called.

Additional descriptor features

method

If you specify method descriptor and assign function to it, contrue will bind the target object to this method.

var obj = construe({}, {
    test: {
        method: function () {
            //in this function `this` is always set to obj
        }
    }
});

bindable

bindable descriptor should be set if you want to user construe.bind(...) method to bind variables.

var obj1 = construe({
  variable: {
    bindable: true
  }
});

var obj2 = construe({
  variable: {
    bindable: true
  }
});

construe.bind(obj1, 'variable', obj2, 'variable');

obj2.variable = 'TEST';
console.log(obj1.variable); //obj1.variable has value of 'TEST' now

bind

bind descriptor invokes construe.bind(...) method. bind descriptor parameter should be an array with 2 elements: an object and a variable.

var obj1 = construe({
  variable: {
    bindable: true
  }
});

var obj2 = construe({
  variable: {
    bind: [obj1, 'variable']
  }
});

obj1.variable = 'TEST';
console.log(obj2.variable); //obj2.variable has value of 'TEST' now

bind2Way

bind2Way descriptor works same as bind descriptor does but it uses construe.bind2Way.

```js
var obj1 = construe({
 variable: {
   bindable: true
 }
});

var obj2 = construe({
 variable: {
   bind2Way: [obj1, 'variable']
 }
});

obj1.variable = '2 way';
console.log(obj2.variable); //obj2.variable has a value of '2 way`

obj2.variable = 'data binding';
console.log(obj1.variable); //obj1.variable has a value of 'data binding' now

onDemand

onDemand descriptor creates a getter which will call onDemand function only once when the property will be "demanded" (when someone will try to get it)

var runs = 0;

var obj = construe({
  variable: {
    onDemand: function () {
      //initialize the variable (this will run only once)
      runs += 1;
      return runs;
    }
});

console.log(obj.variable); //1
console.log(obj.variable); //also 1
console.log(obj.variable); //also 1