Vex NPM | npm.io

Vex

A Schema Validator

Vex is a handy client side and Node module that "proofs" an object according to a supplied schema.

If the object doesn't satisfy the schema, then schema is considered "vexed", thus the object will be rejected.

Install

Node

npm install vex

Then simply require

var vex = require('vex');

Browser

vex.js and vex.min.js are available in the dist folder. Client-side Vex is a UMD bundle generated with Browserify, this means if you're using Require.js or some form of AMD you can load it as a client-side module using your module loader of choice. If not vex is exported to the global scope as vex.

The client code can be generated with

npm run dist

Usage

Basic Example

var schema = {
  name: String
}


function doSomething(config) {
  vex(config, schema);
  //do stuff
}

Pinned Schema

function doSomething(config) {
  vex(config);
  //do things
}

doSomething.schema = {
  name: String
}

Optional and Required

function doSomething(config) {
  vex(config);
  //do stuff
}

doSomething.schema = {
  opt: {
    name: String,
  },
  req: {
    id: Number
  }
}

Argument Schemas

function doSomething(name, id) {
  vex(arguments);
  //do stuff
}

doSomething.schema = [String, {req:{id: Number}}];

String Types

Special types

DOM Types

Multiples types

Assertion Functions

settings.throw

By default Vex will throw if a schema hasn't been fulfilled.

We can turn this behaviour off:

var vex = require('vex');

var schema = {
	name: String
}

function buildAThing(config) {
	if (vex(config, schema)) {
		//handle error state:
		console.error('oh oh', vex.status())
		return;
	}

	//do stuff
}

If a config doesn't satisfy a schema, vex will return true (to let us know it has been vexed). This allows us to validate the schema at the top of the function and return early if there's a problem (that is if vex throwing is turned off).

If vex returned false when the schema wasn't satisfied we'd either have to preceed the check with a not (!) or otherwise handle problems at the bottom of the function with an else statement - which would create an extra level of nexting and put error handling in an unintuitive place (at the bottom).