JavaScript Truthy and Falsey

falsey.js

function falsey( val ) {
        return !(
            val === 'undefined' ||
            val === undefined ||
            val === false ||
            val === "false" ||
            val === "off" ||
            val === "OFF" ||
            val === "Off" ||
            val === null ||
            val === 'null' ||
            val === 'NaN' ||
            val === NaN ||
            val === 0 ||
            val === "0" ||
            val === '')
    }