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

Created by bdukesLinked to 75.3m issues across 157 teams

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.