How to check if value in JS is not null and not empty string


mistery_girl:

Is it possible to check if a value is not null and not an empty string in Java? I am using one of the following:

var data; //get its value from db 
if(data != null && data != '') {
   // do something
}

But I wonder if there is another better solution. thanks.

Gershon Papi:

If you really want to confirm that the variable is not null, and not specifically an empty string, you can write:

if(data !== null && data !== '') {
   // do something
}

Note, I changed the code to check for type equality ( !==| ===).

However, if you just want to make sure your code only runs for "reasonable" values, you can write as others have already pointed out:

if (data) {
  // do something
}

Because in javascript both null value and empty string are equal to false (ie null == false).

The difference between these two code sections is that for the first section every value that is not specifically null or an empty string will be entered if. However, in the second, every real-ish value will go in if: false, 0, null, undefinedand the empty string, which won't.

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