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

问题

This question already has answers here:

Get array of object's keys (7 answers)

Closed 4 years ago.

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?

回答1:

Object.keys()

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

回答2:

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);
}
}

来源：https://stackoverflow.com/questions/31542654/form-array-of-property-names-found-in-a-javascript-object