const a = 1;
const b = 2;
let foo;

if (!a < b) {
    /**/
}

while (!a > b) {
    /**/
}

foo = !a <= b;

foo = !a >= b;

const myObject = {};
const key = "";
const Ctor = Function;

if (!key in myObject) {
    // operator precedence makes it equivalent to (!key) in object
    // and type conversion makes it equivalent to (key ? "false" : "true") in object
}

if (!myObject instanceof Ctor) {
    // operator precedence makes it equivalent to (!obj) instanceof Ctor
    // and it equivalent to always false since boolean values are not objects.
}