validate-arguments-js

Validate arguments, declarative.

Installation

    npm install validate-arguments

The code itself depends on lodash, and will propably run just fine in the browser using require.js.

Documentation

This module levarages some of the validation methods from lodash, but by offering you a declaritive syntax and nice error strings:

• array
• boolean
• date
• element
• empty
• finite
• function
• null
• number
• object
• plainObject
• regexp
• string

And adds the following additional ones:

• whole ( An integer )
• real ( A real number that isn't NaN )
• natural ( Positive integer )
• primitive ( 'number', 'boolean', 'string' )

When passing a constructor (function) as an isa, an instanceof check is done.

    var Validate = require('validate-arguments');
    
    function doSomething(withNamedArguments) {
        var args = Validate.named(arguments, {
            number: 'whole',
            name: 'string'
            callback: 'function'
            options: {
                isa: 'plainObject',
                optional: true
            },
            validation: Validate // performs an instanceof
        });
    
        if (!args.isValid()) {
            throw args.errorString();
        }
    
        // continue safely
    }

Look at the test cases for more examples.

Node that validations may be nested:

    var args = Validate.named(arguments, {
        address: {
            primary: {
                street: 'string',
                housenumber: 'number'
            }
        },
    });

Methods

named( named, validationSpec )

Returns a validationObject for further inspection. named should be a non-empty plain Object, containing all the keys documented in the validationSpec. The validationSpec should be an object, where the keys match the desired input. You may use the form { thing: 'string' } over { thing: { isa: 'string' } }.

When passed an arguments object instead of a plain object, the first key of the arguments is used.

positional( arguments, ... )

Validate positional arguments, either an array or arguments object. Spec may be provided as an array in the second argument, or a variable number of arguments.

validate( arguments, ... )

Validate arguments, freeform.

If the second argument contains a string, it is treated as a positional argument with one element.

Return values

Both validateObject and validatePositional return a validationObject with the following methods:

• isValid: A boolean indication the validness
• errors: An array containing positions or keys of invalid arguments
• get: Retrieve values from the original input, array index or key
• values: Return an array of values ( not that usable )
• errorString: An error string explaining what went wrong (verbosely)

Testing

cd validate-arguments-js
npm install
npm test