How to check for an undefined or null variable in JavaScript?

Question

We are frequently using the following code pattern in our JavaScript code

if (typeof(some_variable) != \'undefined\' && some_variable != null)
{
             


        

Answer 1

Best way to compare undefined or null or 0 with ES5 and ES6 standards

 if ((Boolean(some_variable_1) && Boolean(some_variable_2)) === false) {
    // do something
    }