What is the best way to check if a variable is set?

2018-07-04 02:45:34

This question already has an answer here:

JavaScript check if variable exists (is defined/initialized) 28 answers

check it using typeof

if(typeof(a) != "undefined") {
     //code goes here
}

Here are some related questions.

How can I check whether a variable is defined in JavaScript?

Test if a variable is defined in javascript?

if (typeof a !="undefined")
{
 //write your code here
}

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