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fp-curry.js
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36 lines (29 loc) · 1015 Bytes
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'use strict';
const curry = (fn) => (...args) => args.length >= fn.length
? fn(...args)
: (...rest) => curry(fn)(...args, ...rest);
// Implementation
const validatePoint = (x, y) => {
const errors = [];
if (!Number.isFinite(x)) errors.push(new TypeError(`Invalid x: ${x}`));
if (!Number.isFinite(y)) errors.push(new TypeError(`Invalid y: ${y}`));
return errors;
};
const createPoint = curry((x, y) => {
const errors = validatePoint(x, y);
if (errors.length > 0) {
const cause = new AggregateError(errors, 'Validation');
throw new RangeError('Bad coordinates', { cause });
}
return Object.freeze({ x, y });
});
const move = curry(({ x, y }, dx, dy) => createPoint(x + dx)(y + dy));
const clone = curry((point) => createPoint(point.x)(point.y));
const toString = curry((point) => `(${point.x}, ${point.y})`);
// Usage
const p1 = createPoint(10)(20);
console.log(toString(p1));
const c0 = clone(p1);
console.log(toString(c0));
const c1 = move(p1)(-5)(10);
console.log(toString(c1));