SOURCE

// instanceOf
const _instanceOf = (obj, func) => {
    if (obj === null || typeof obj !== 'object') {
        return false
    }
    let proto = Object.getPrototypeOf(obj)
    while (true) {
        if (proto === func.prototype) {
            return true
        } else if (proto === null) {
            return false
        } else {
            proto = Object.getPrototypeOf(proto)
        }
    }
}