value

The initial value of the Boolean object.

When Boolean() is called as a constructor (with new), it creates a Boolean object, which is not a primitive.

When Boolean() is called as a function (without new), it coerces the parameter to a boolean primitive.

The value passed as the first parameter is converted to a boolean value. If the value is omitted or is 0, -0, 0n, null, false, NaN, undefined, or the empty string (""), then the object has an initial value of false. All other values, including any object, an empty array ([]), or the string "false", create an object with an initial value of true.

const bZero = new Boolean(0);
const bNull = new Boolean(null);
const bEmptyString = new Boolean("");
const bfalse = new Boolean(false);

typeof bfalse; // "object"
Boolean(bfalse); // true

Note how converting a Boolean object to a primitive with Boolean() always yields true, even if the object holds a value of false. You are therefore always advised to avoid constructing Boolean wrapper objects.

If you need to take the primitive value out from the wrapper object, instead of using the Boolean() function, use the object's valueOf() method instead.

const bfalse = new Boolean(false);

bfalse.valueOf(); // false

• Boolean