how do i check if an object has a key in javascript ?

Question

which is the right thing to do?

if (myObj['key']==undefined)

or

if (myObj['key']==null)

or

if (myObj['key'])

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Exact duplicate of: http://stackoverflow.com/questions/135448/how-do-i-check-to-see-if-an-object-has-an-attribute-in-javascript

Answer 1

hasOwnProperty

Answer 2

Try the javascript in operator.

if('key' in myObj)