validateParams.js (@maynoothuniversity/validate-params)

A wrapper around validate.js to facilitate easy function parameter validation in JavaScript.

validate.js is designed to validate web forms. HTML form data is fundamentally a collection of name-value pairs, so it makes sense that the validation functions provided by validate.js expect both the data to be validated, and the constraints to be applied to that data to be specified as collections of name-value pairs (JavaScript objects).

Function parameters are not name-value pairs, they are lists of values. Hence, the validation functions provided by this module expect both the data to be validated, and the constraints to be applied to that data to be specified as lists.

Internally, the module converts the passed parameter and constraint lists to collections of name-value pairs which it then validates with validate.js.

As well as translating between lists and name-value pairs, the module also provides a number of other additional features which focus on parameter validation, including the specification of default values, support for data coercion, improved support for nested constraints, and a number of additional validators.

Installation

NodeJS

Install the module and its dependencies:

npm install '@maynoothuniversity/validate-params' --save

Load the module:

var validateParam = require('@maynoothuniversity/validate-params');

Browser (CDN)

<!-- Import validate.js then validateParams.js -->
<script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/validate.js/0.11.1/validate.min.js"></script>
<script type="text/javascript" src="https://cdn.rawgit.com/bbusschots-mu/validateParams.js/master/validateParams.js" ></script>

Synopsis:

// passes through the return value from validate.js
var errors = validateParams(parameterList, constraintList, [options]);

or

// returns a validateParams.Result object
var result = validateParams.validate(parameterList, constraintList, [options]);

// throws a validateParams.ValidationError if validation fails
validateParams.assert(parameterList, constraintList, [options]);

The parameterList can be an array, or, JavaScript's special arguments variable.

The constraintList is an array of object literals, each defining one or more validate.js compatible constraints.

The optional options parameter should be an object literal, and can be used to specify options that alter both the behaviour of the validation functions provided by this module, and the validation functions from validate.js used to perform the actual validations.

Example

// An implementation of the Factorial function
// The first argument must be present, an integer, and >= 0
function fact(n){
    // validate the parameter
    validateParams.assert(
        arguments,
        [{
            presence: true,
            numericality: {
                onlyInteger: true,
                greaterThanOrEqualTo: 0
            }
        }
    ]); // will throw a validateParams.ValidationError on invalid params
    
    // do the calculation
    var ans = 1;
    while(n > 0){
        ans *= n;
        n--;
    }
    
    // return the result
    return ans;
}

var x = fact(4); // x=24
var y = fact('4'); // x=24
var z = fact('stuff'); // throws validateParams.ValidationError

Documentation

• API Documentation for validateParams.js: bbusschots-mu.github.io/...
• API Documentation for validate.js: validatejs.org/...