Chaining pipe

chained.pipe.js

const _makeProxy = f => new Proxy(f, {
	get (fn, prop) {
		return U[prop] && U[prop].bind({ hold: fn });
	}
});

const U = {
	add: function (x) {
		return _makeProxy(
			y => (
				this.hold && (y = this.hold(y)),
				x + y
			));
	},
	multiply: function (x) {
		return _makeProxy(
			y => (
				this.hold && (y = this.hold(y)),
				x * y
			));
	},
	eqBy: function (f) {
		return x => _makeProxy(
			y => (
				this.hold && (y = this.hold(y)),
				f(x) === f(y)
			));
	}
};

console.log(( U.multiply(3).add(4) )(2)); // 10
console.log(( U.add(3).multiply(4).multiply(3) )(2)); // 60
console.log(
	U
	.add(3)
	.multiply(4)
	.multiply(3)
	.eqBy(Math.abs)(60)
		(2)); // true