how to create a copy of json object in javascript instead of a reference

Question

i have testdata.js file with json test data as below:

testdata.js file:

module.exports =

{ createHost: {

        name : "System-001",
        description: "Creating System",

    }

}

In another test, I am trying to create a variable called testcase1 with the above test data. Changing the property value in testcase1, changes the value in the testdata.js file json object.

it("Create a host", function(){
var testcase1 = testdata.createHost;

testcase1.name="sys-002";

console.log(testcase1.name);
console.log(testdata.createHost.name);
});

Response: sys-002 sys-002

My requirement is to create a copy of testdata instead of creating a reference. How can I do this?

score 7 · Accepted Answer · answered May 27 '16 at 14:55

7

Shortest way:

var copied = JSON.parse(JSON.stringify(object));

answered May 27 '16 at 14:55

Azamantes

1,435
10
15

Thanks **@Azamantes** for your answer.It worked .. – saradhi ramakrishna May 30 '16 at 05:58

score 0 · Answer 2 · answered May 27 '16 at 13:52

You can use a for in loop to loop through each of the properties and assign them by value.

var createHost = { name : "System-001", description: "Creating System" }
var test = {};
for (var key in createHost)
 test[key] = createHost[key];
  
test.name = "Test";

console.log(test.name);
console.log(createHost.name);

score 0 · Answer 3 · answered May 27 '16 at 13:54

0

You can use the extend function in jQuery to clone the object:

var testCaseClone = jQuery.extend({}, testdata);

answered May 27 '16 at 13:54

ux11

158
2
13

score 0 · Answer 4 · edited May 23 '17 at 11:46

There's no such thing as "JSON object" (unless you literally mean global object that holds parse and stringify functions). There are only JSON strings. As such you copy them using simple = operator.

var copy_json_string = original_json_string

If you need to copy an object instead (it is object, just object, not "JSON object"), there are dozens of answers already, for example at: How do I correctly clone a JavaScript object?.

how to create a copy of json object in javascript instead of a reference

4 Answers4