How do I check for an empty/undefined/null string in JavaScript?

tl;dr

You can check for an empty/undefined/null string in JavaScript using truthy and falsy checks.

For example, you can use the Boolean() function to check if a string is empty/undefined/null:

let str = '';
let result = Boolean(str);
console.log(result); // Output: false

In the example above, the Boolean() function returns false because the string str is empty.