Is there a standard function to check for null, undefined, or blank variables in JavaScript?

Question

Is there a universal JavaScript function that checks that a variable has a value and ensures that it\'s not undefined or null? I\'ve got this code,

Answer 1

Here's mine - returns true if value is null, undefined, etc or blank (ie contains only blank spaces):

function stringIsEmpty(value) {

    return value ? value.trim().length == 0 : true;

}