Changing the values of all the objects in an array using Underscore

Question

I have an array of objects containing a property called 'memory' whose value is in MB. I need to convert the array containing the object with 'memory' value in GB. How can I do it using Underscore.js.

Below is the code:

 var parseSize = function(obj){
   if (obj === 0 ){
    return 0;
   } else {
     return  parseFloat(obj/1024).toFixed(2);
   }
 }

   var testData=[
       { name: 'ddd',Vcpu: 2, memory: 4096, os: 'Microsoft Windows Server 2008 (32-bit)'}, 
       { name: 'eee',Vcpu: 2, memory: 2040, os: 'Microsoft Windows Server 2008 (32-bit)'},
       { name: 'ddd',Vcpu: 2, memory: 4096, os: 'Microsoft Windows Server 2008 (32-bit)'}, 
       { name: 'eee',Vcpu: 2, memory: 2040, os: 'Microsoft Windows Server 2008 (32-bit)'}
   ];

  testData =_.invoke(testData , function(){
              testData['memory'] = parseSize(testData['memory']) + " GB";
            });
  console.log(testData);

The above code is not working. PLease let me know where I am going wrong.

Adding the Jsfiddle link: http://jsfiddle.net/prashdeep/k29zuba2/

Kenny Ki · Accepted Answer · 2014-09-09 08:51:06Z

2

The answer of what went wrong in your code:

You should use _.each
You should not reassign testData with the result
You should be accessing "memory" property on each item in testData, not on testData itself

So change your latter part of code to:

_.each(testData , function(datum){
    datum['memory'] = parseSize(datum['memory']) + " GB";
});

console.log(testData);

answered Sep 9, 2014 at 8:51

Kenny Ki

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Comments

elclanrs · Accepted Answer · 2014-09-09 08:45:09Z

1

You can use map. This is built into JavaScript since ES5:

var result = testData.map(function(x) {
    x.memory = parseSize(x.memory) + ' GB'
    return x
})

answered Sep 9, 2014 at 8:45

elclanrs

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Comments

Vlad Nicula · Accepted Answer · 2014-09-09 08:52:31Z

1

Using underscore _.each you can do the following:

 _.each(testData , function( item ){
    item['memory'] = parseSize(item['memory']) + " GB";
 });

See jsfiddle example.

Don't use map or forEach if you want support for older browsers like IE8.

answered Sep 9, 2014 at 8:52

Vlad Nicula

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Comments

saikiran.vsk · Accepted Answer · 2014-09-09 08:47:14Z

0

var parseSize = function(obj){
   if (obj === 0 ){
    return 0;
   } else {
     return  parseFloat(obj/1024).toFixed(2);
   }
 }

   var testData=[
       { name: 'ddd',Vcpu: 2, memory: 4096, os: 'Microsoft Windows Server 2008 (32-bit)'}, 
       { name: 'eee',Vcpu: 2, memory: 2040, os: 'Microsoft Windows Server 2008 (32-bit)'},
       { name: 'ddd',Vcpu: 2, memory: 4096, os: 'Microsoft Windows Server 2008 (32-bit)'}, 
       { name: 'eee',Vcpu: 2, memory: 2040, os: 'Microsoft Windows Server 2008 (32-bit)'}
   ];

  testData.forEach(function(d){ d.memory = parseSize(d.memory); });

  console.log(testData);

answered Sep 9, 2014 at 8:47

saikiran.vsk

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