validation.js

/*
 * There are 2 {validation} patterns. There is always place for both of them. How do I do the second one?
 * 1. Validate against different validators and return the first failure.
 * 2. Validate against different validators and return all the failures.
 */

/* 1. Compose and terminate with first failure */
const validateMinMagicNumber = (min_magic) => ( // accepts a number and returns string with the first error.
  isEmpty(min_magic, 'Min Magic is required') ||
    failedParseNumber(min_magic) ||
    outsideOfMagicRange(parseNumber(min_magic), 'Min Magic should be between 1 and 9999') ||
    isGreaterThan(parseNumber(min_magic), parseNumber(MAX_MAGIC), 'Min Magic cannot be greater than MAX MAGIC') ||
    isGreaterThan(parseNumber(min_magic), parseNumber(AVG_MAGIC), 'Min Magic cannot be greater than AVG Magic')
);

/* 2. Compose and collect all failures, lift them into dictionary */
/* Let's say, <*> is an operator which creates a tupple or some sort of collection of arguments,
              <?> is a function with runs apply of these arguments on the next function */
const validateMagicValuesX = (min_magic, avg_magic, max_magic) => (
  return (validateMinMagicNumber(min_magic) <*> validateAvgMagicNumber(avg_magic) <*> validateMaxMagicNumber(max_magic)) <?> 
    ((minError, avgError, maxError) => {"minMagic": minError, "avgMagic": avgError, "maxMagic": maxError})
);

/* 2. Compose and collect all failures, lift them into dictionary */
const validateMagicValuesY = (min_magic, avg_magic, max_magic) => (
  const errors = {};
  errors.minMagic = validateMinMagicNumber(min_magic);
  errors.avgMagic = validateAvgMagicNumber(avg_magic);
  errors.maxMagic = validateMaxMagicNumber(max_magic);
  return errors;
);