Draconian NPM | npm.io

Draconian

Draconian is an ultity library for declaratively defining parameter constraints in JavaScript functions. It believes function parameter validation should be extracted from the function itself, and written in a declarative way such that the resulting code is clean and elegant. The parameter validation declaration should also server as documentation that is guaranteed to be up to date.

Setup

To install:

npm install draconian

Or add the following line to your package.json's dependencies object:

"draconian": "*"

To contribute as a developer, you'll need Mocha for run the tests via:

npm test

API

Draconian'ize a function by doing the following:

// non-named parameter functions
var regularFunc = Drac.regular({
  params: {
    num1: { type: 'number' },
    num2: { type: 'number', optional: true },
    str: { type: 'string' }
  }
}, function(num1, num2, str) { return num1 + num2 + str; });

// named parameter functions
var asyncFunc = Drac.async({
  params: {
    num1: { type: 'number' },
    num2: { type: 'number' },
    str: { type: 'string' }
  }
}, function(options, callback) {
  var result = options.num1 + options.num2 + options.str;
  return callback(null, result);
});

// NOTE: only strings are allowed for parameter names

And call it:

regularFunc(1, 2, 'hi'); // ouputs 3hi
regularFunc(1, 2, 3); // exception!
asyncFunc({ num1: 1, num2: 2 }, function() {}); // exception!

Parameter Options

// type
// JavaScript native type
// { type: 'number' }

// instance
// JavaScript parent constructor function, same as instanceof
// { instance: Array }

// match
// JavaScript string regex match
// { match: /abcde/ }

// notMatch
// opposite of match
// { notMatch: /abcde/ }

// isEmail
// whether the parameter matches /^[a-zA-Z0-9._-]+@[a-zA-Z0-9._-]+$/
// { isEmail: true }

// isUrl
// whether the parameter matches /^https?:\/\/[a-zA-Z0-9\/._-]+$/
// { isUrl: true }

// notNull
// whether the parameter cannot be null
// { notNull: true }

// notEmpty
// whether the parameter cannot be empty
// { notEmpty: true }

// isIn
// whether the parameter is one of predefined values
// { isIn: ['hello', 3, false] }

// notIn
// whether the parameter is not one of predefined values
// { notIn: ['hello', 3, false] }

// len
// whether the parameter length is within predefined range
// { len: [2, 5] }

// min
// whether the parameter is above or equal to min value
// { min: 0 }

// max
// whether the parameter is below or equal to max value
// { max: 0 }

// range
// whether the parameter is inside (inclusive) range
// { range: [-5, 5] }

// isDate
// whether the parameter can be converted to date
// { isDate: true }

// isISODate
// whether the parameter is an ISO date string
// { isISODate: true }

// optional
// whether the parameter can be undefined
// { optional: true }