Assignment: curried function with => notation

Write a function named plus that returns the sum of its arguments, where the arguments are being passed in curried style, such that for all numbers x and y, plus(x)(y) === x + y. Use the => notation exclusively, i.e. no function keyword.

const plus = x => y => x + y;

Your solution will be tested against:

const x_ = Math.random();
const y_ = Math.random();
const plus3 = plus(3);
plus(x_)(y_) === x_ + y_ && plus3(y_) === 3 + y_;