How to return object from function?

Question

I am having conceptual Javascript issues while returning Object from functions. Can someone point out what am I doing wrong here?

var productsPartsObj = {
  layers: ['toe', 'base', 'shaft'],
  layer: [
    {
      name: 'toe',
      height: 75,
      width: 78,
      coords: {
        x: 20,
        y: 120
      }
    }
  ]
}

var coords = {};
coords = (function() {
  productsPartsObj.layer.forEach(function(layerObj){
    if ( layerObj.name === "toe" ) {
      return layerObj.coords;
    }
  })
})()

console.log(coords); //logs undefined

James Allardice · Accepted Answer · 2013-04-17 06:46:14Z

You are returning from the forEach callback, not from the immediately-executed function expression. You could do this instead (assuming you know there will only ever be one element of the layer array with a name matching the value in question:

var coords = (function() {
  return productsPartsObj.layer.filter(function(layerObj){
      return layerObj.name === "toe";
  })[0].coords;
})();

Notice that there are 2 return statements - the first one returns from the IIFE, and the second returns from the filter callback.

Also notice that I've moved the var keyword into this statement. There is no point assigning an empty object to coords and then simply overwriting it.

Arun P Johny · Accepted Answer · 2013-04-17 06:48:04Z

Your anonymous function is not returning any value.

var productsPartsObj = {
    layers : ['toe', 'base', 'shaft'],
    layer : [{
                name : 'toe',
                height : 75,
                width : 78,
                coords : {
                    x : 20,
                    y : 120
                }
            }]
}

var coords = {};
coords = (function() {
    var x;
    productsPartsObj.layer.forEach(function(layerObj) {
                if (layerObj.name === "toe") {
                    x = layerObj.coords;
                }
            })
    return x;
})()

console.log(coords);

Else set the coords value directly using

var coords = {};
(function() {
    productsPartsObj.layer.forEach(function(layerObj) {
                if (layerObj.name === "toe") {
                    coords = layerObj.coords;
                }
            })
})()

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