بناء pipe وcompose

من دالتين إلى دوال متعددة

pipe: من اليسار إلى اليمين

const pipe = (...fns) => x => fns.reduce((acc, fn) => fn(acc), x);

const inc = n => n + 1;
const double = n => n * 2;

console.log(pipe(inc, double)(5));

كيف تُحرّك reduce الدالة pipe

const pipe = (...fns) => x => fns.reduce((acc, fn) => fn(acc), x);

const steps = pipe(
  n => n + 1,
  n => n * 3,
  n => n - 2
);

console.log(steps(4));

compose باستخدام reduceRight

const compose = (...fns) => x => fns.reduceRight((acc, fn) => fn(acc), x);

const inc = n => n + 1;
const double = n => n * 2;

console.log(compose(inc, double)(5));

pipe وcompose صورتان متعاكستان

const pipe = (...fns) => x => fns.reduce((acc, fn) => fn(acc), x);
const compose = (...fns) => x => fns.reduceRight((acc, fn) => fn(acc), x);

const inc = n => n + 1;
const square = n => n * n;

console.log(pipe(inc, square)(3));
console.log(compose(inc, square)(3));

compose بوصفها pipe معكوسة

const pipe = (...fns) => x => fns.reduce((acc, fn) => fn(acc), x);
const compose = (...fns) => pipe(...fns.reverse());

const inc = n => n + 1;
const double = n => n * 2;

console.log(compose(inc, double)(5));

خط أنابيب نصي حقيقي

const pipe = (...fns) => x => fns.reduce((acc, fn) => fn(acc), x);

const slugify = pipe(
  s => s.trim(),
  s => s.toLowerCase(),
  s => s.replace(/\s+/g, '-')
);

console.log(slugify('  Hello World Example  '));

تركيب عمليات المصفوفات

const pipe = (...fns) => x => fns.reduce((acc, fn) => fn(acc), x);

const process = pipe(
  arr => arr.filter(n => n % 2 === 0),
  arr => arr.map(n => n * 10)
);

console.log(process([1, 2, 3, 4, 5, 6]));

حالة الحافة الخاصة بالهوية

const pipe = (...fns) => x => fns.reduce((acc, fn) => fn(acc), x);

const identity = pipe();
console.log(identity(42));
console.log(identity('unchanged'));

الدمج مع Currying

const pipe = (...fns) => x => fns.reduce((acc, fn) => fn(acc), x);
const add = a => b => a + b;
const times = a => b => a * b;

const calc = pipe(add(3), times(2), add(-1));
console.log(calc(5));

اختيار pipe أو compose

const pipe = (...fns) => x => fns.reduce((acc, fn) => fn(acc), x);

const normalize = pipe(
  s => s.trim(),
  s => s.replace(/[^a-z0-9]+/gi, ' '),
  s => s.toUpperCase()
);

console.log(normalize('  a-b_c!d  '));

اختبار سريع

مراجعة: pipe وcompose