Convert truthy or falsy to an explicit boolean

Question

I have a variable. Let\'s call it toto.

This toto can be set to undefined, null, a string, or an object.

Answer 1

Yes, you can always use this:

var tata = Boolean(toto);

And here are some tests:

for (var value of [0, 1, -1, "0", "1", "cat", true, false, undefined, null]) {
    console.log(`Boolean(${typeof value} ${value}) is ${Boolean(value)}`);
}

Results:

Boolean(number 0) is false
Boolean(number 1) is true
Boolean(number -1) is true
Boolean(string 0) is true
Boolean(string 1) is true
Boolean(string cat) is true
Boolean(boolean true) is true
Boolean(boolean false) is false
Boolean(undefined undefined) is false
Boolean(object null) is false

Answer 2

You can use Boolean(obj) or !!obj for converting truthy/falsy to true/false.

var obj = {a: 1}
var to_bool_way1 = Boolean(obj) // true
var to_bool_way2 = !!obj // true