Validates the structure of Jav

ValidateJS

Validates the structure of JavaScript objects.

Why

As soon as you start using JavaScript on the server side, it becomes useful to send JSON data between the server and client. However, you soon run into the problem that the client might send you a JSON string that is valid (JSON.parse wont't throw an error), but the returned JavaScript object doesn't have the structure you expect:

var obj = JSON.parse(body); var name = obj.name.trim();

This will work fine... as long as the name property is a string. If you got a number back, this will crash your Node process, as there is no trim function on the Number.prototype.

To get around this, you could surround everything with an try/catch but that slows down the execution speed of your app as well as doesn't guarantee that everything works as expected. If you expect to get back a non floating number, but you got a floating number, things will work out, until you write the number to a MySQL database, that expects to get an integer number and converts the floating number to an integer one. E.g. you got the number 1.1 and tested it to be 1, which is false of cause but then MySQL converts it to 1 again - that can break your App's logic or even worse allows the user to hack your app.

Validate Your Input

This is where ValidateJS comes in:

var V = require("validate"); [...] // Parse the JSON string to get an JavaScript object. var obj = JSON.parse(body); // Define the structure that the JavaScript object should have. var objStructure = V.Object({ name: V.String }); // Validate it. var valid = V.validate(obj, objStructure); // Let's see, if the object is valid. if (valid !== true) { // Hacking! } else { // Everyting is fine! }

Doing this kind of validation is fast and easy, but makes your app way more secure.

If you like using callbacks, you can also write:

V.validate(obj, objStructure, function(err) { ... }); Documentation

At this point, there is no real documentation, but you can checkout the test.js file, that contains the unit tests and has some comments + examples that should make it easy to get started.

Currently, you can validate

the types: Object, Array, String, Number (floating number + non floating number), Integer, Boolean define test functions for properties declare that some properties are only expected in some cases (using the onlyIf statement) turn strictMode on and off (on by default) Testing

I've created this for a small side project of mine and tested it so far on the project as well as using the unit tests in test.js. Expect to find bugs. By now, this is tested on NodeJS, but you might be able to use this on modern browsers as well.