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const plusOne = a => a + 1;
const plusTwo = a => a + 2;

const composedPlusThree = a => plusTwo(plusOne(a));

composedPlusThree(3); // 6

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const compose = (...fns) => x => fns.reduceRight((v, f) => f(v), x);
const composePipe = (...fns) => x => fns.reduce((v, f) => f(v), x);

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const plusA = s => s + 'A';
const plusB = s => s + 'B';

const composed1 = s => compose(plusA, plusB)(s);
const composed2 = s => composePipe(plusA, plusB)(s);

composed1(''); // BA
composed2(''); // AB

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const composedPointFree = compose(plusA, plusB);

console.log(composedPointFree('') === composed1('')); // true

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function simonSays(arg) {
  let result = arg.trim();
  result = `Simon Says: ${result}`;
  return result;
}

simonSays(' Jump! '); // Simon Says: Jump!

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const trim = a => a.trim();
const add = a => b => a + b;

const simonSays = composePipe(trim, add('Simon Says: '));

simonSays(' Jump! '); // Simon Says: Jump!

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const add = a => b => a + b;
const partialSimonSays = add('Simon Says:'); // partial application
const simonSays = composePipe(trim, partialSimonSays);

partialSimonSays('Jump!'); // Simon Says: Jump!
simonSays(' Jump! '); // Simon Says: Jump!

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// console.log is impure and does not provide any return value
// so we have to improve it
const investigate = a => console.log(a) || a;

const simonSays = composePipe(
  investigate,
  trim,
  investigate,
  partialSimonSays,
  investigate

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import {bark} from './dog';
import {compose} from './functional';

const doubleIt = a => 2 * a;

export const roboBark = composePipe(bark, doubleIt);

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const arrowFunction = (arg1, arg2) => arg1 + arg 2;

const traditionalFunction = function(arg1, arg2) {
  return arg1 + arg2;
};