Form array of property names found in a JavaScript Object [duplicate]

Question

I have the following object

var columns = {ContributionType: "Employer Contribution",
               Employee1: "0",
               Employee2: "0",
               Employee3: "0"
              };

From this I need to form an array with they property keys alone like following

var keys=["ContributionType", "Employee1", "Employee2", "Employee3"];

The number of properties is dynamic

Question: How can I achieve this using lodash or pure JavaScript?

epascarello · Accepted Answer · 2015-07-21 14:59:28Z

1

Object.keys()

var columns = {ContributionType: "Employer Contribution",
               Employee1: "0",
               Employee2: "0",
               Employee3: "0"
              };
var keys = Object.keys(columns);
console.log(keys);

answered Jul 21, 2015 at 14:59

epascarello

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Comments

Untimely Answers · Accepted Answer · 2015-07-21 20:39:27Z

1

var arr=[];
for (var key in columns)
{
//by using hasOwnProperty(key) we make sure that keys of
//the prototype are not included if any
if(columns.hasOwnProperty(key))
{
    arr.push(key);
}
}

edited Jul 21, 2015 at 20:39

answered Jul 21, 2015 at 15:02

Untimely Answers

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2 Comments

Phylogenesis Over a year ago

Be careful when using a loop like this. You may want to check obj.hasOwnProperty(key) to check that keys aren't being added by a prototype.

Untimely Answers Over a year ago

Thanks for pointing that out.

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