Typescript string empty check is not working

Question

how to validate white space to false. am using if (value) to check value. method2 prints true. is there any method to check white space string like this ' '

 method1() {
    this.method2(' ');
  }

  method2(value) {
    debugger;
    if (value) {
      console.log("true");
    } else {
      console.log("false");
    }
  }

You're not checking whether a string is empty, you're just checking whether it is _truthy_. In JavaScript (and by extension, TypeScript), a string containing one space is considered to be _true_. — Tom Fenech, Nov 22 '17 at 13:44

score 1 · Answer 1 · answered Nov 22 '17 at 13:24

The string isn't really empty. There is a whitespace.

You could check for Null and Whitespace like that:

function isEmpty(input){
    return (input.replace(/\s/g, "").length > 0 ? false : true);
}

Using the code like this:

method2(value) {
    //...
    if (!isEmpty(value)) {
        console.log("true");
    } else {
        console.log("false");
    }
}

Typescript string empty check is not working

1 Answers1