While I was working on a project, I came across this snippet of code:
var params = JSON.parse(JSON.stringify(defaultParams));
Does this code actually do anything?
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4It can create a simple clone of the object. Note the 2nd answer by Corban Brook.Jonathan Lonowski– Jonathan Lonowski2014-07-14 19:39:21 +00:00Commented Jul 14, 2014 at 19:39
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3It also validates that the object is serializable (it contains only primitives & no cycles).tcooc– tcooc2014-07-14 19:44:28 +00:00Commented Jul 14, 2014 at 19:44
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2 Answers
It's a way of cloning an object, so that you get a complete copy that is unique but has the same properties as the cloned object.
var defaultParams = { a : 'b' };
var params = JSON.parse(JSON.stringify(defaultParams));
console.log( params.a ); // b
console.log( defaultParams.a ); // b
console.log( params === defaultParams ); // false
The above outputs false because even though both objects have the a property, with the value b, there are different objects that are independent of each other (they don't refer to the same reference).
The JSON method will only work with basic properties - no functions or methods.
2 Comments
Dalibor
After years of using this "trick", I just realized - it messes up the date!! I got date property in output object in ISO format, as if I was invoking toISOString() method on it!
DharmaTurtle
More cons of using this method of cloning given here: medium.com/@pmzubar/… It also messes up on NAN and Infinity.
You can break the connection between two arrays.
For example:
const bulkAssignTreeView = JSON.stringify(this.bulkAssignTreeViewData);
this.bulkAssignTreeViewData = JSON.parse(bulkAssignTreeView);
