@tmurphree/validation-predicates v2.0.4

validation-predicates

Why

Functions that take some of the pain out of validating input. Turns validation syntax into readable, easily-combinable functions. This makes you more likely to do it.

There are other great libraries out there that do similar things:

• Generic validators

• String validation

Please use them if you're looking for a different take on the same subject.

Change log

Link to changes

Installation

npm install --save @tmurphree/validation-predicates

Usage

const { 
  isNumberGreaterThan,
  isPopulatedArray,
  isString,  
} = require('@tmurphree/validation-predicates');

// the old way: not as readable
// const firstIsValid = function firstIsValid(x) {
//   return typeof x === 'number' &&
//     x > 5;
// };
//
// const secondIsValid = function secondIsValid(x) {
//   return Array.isArray(x) &&
//      x.length > 0 &&
//      x.every((el) => typeof el === 'string') &&
//      x.every((el) => el.length > 2);
// };

// the same tests using validation-predicates 
const firstIsValid = function firstIsValid(x) {
  return isNumberGreaterThan(x, 5);
};

const secondIsValid = function secondIsValid(x) {
  return isPopulatedArray(x) &&
    x.every(isString) &&
    // mix and match with predicates not in the package
    x.every((el) => el.length > 2);
};

const someFunction = function someFunction(first, second) {
  if (!(firstIsValid(first))) {
    throw new Error('Expected first to be a number > 5.');
  }

  if (!(secondIsValid(second))) {
    throw new Error('Expected second to be an array of strings longer than 2 characters.');
  }

  // amazing code goes here
};

someFunction(42, ['some','array']);

Strict mode

Some functions have options. Strict mode is a convenient way to set some of the options. You can always, in both modes, set the options manually.

Without strict mode:

const { isDate, isObjectLike } = require('@tmurphree/validation-predicates');

// isDate, which has no options, is not changed

// isObjectLike(a, b) is called with { checkType: false } by default
// but you can still call isObjectLike(a, b, { checkType: true })

With strict mode:

const { isDate, isObjectLike } = require('@tmurphree/validation-predicates').strict;

// isDate, which has no options, is not changed

// isObjectLike(a, b) is called with { checkType: true } by default
// but you can still call isObjectLike(a, b, { checkType: false })

Functions

• All functions return boolean.
• Parameters not in brackets are required.
• Parameters in brackets are optional.
• 'x' in the parameters list is the thing you want to test.