Stefie

Superlight, schema-based, extensible Node.js object validator. Useful for Express req.body/params/query, or MongoDB document before inserting into collection if don't want to use Mongoose.

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What's New in 2.0.2

• Added numberString type to check for number strings

What's New in 2.0.1

• Added jsonString type to check for JSON strings

What's New in 2.0

• Extensiblity - Add your own custom validators with the add() method
• Cleaner namespace management - put all your rules in the _rules object for each property in the schema
• Code rewritten to be simpler and more elegant
• Added dateString type to check for valid date strings
• Renamed ObjectID type to objectId to be consistent with other type names
• Renamed hexString type to objectIdString to be more intuitive

Installation

$ npm install stefie

Usage

Firstly, model a schema of the object you want to validate. Then, call stefie and see if she returns an error or null.

var stefie = require('stefie');

var movie = {
	title: '300',
	crew: {
		director: 'Zack Snyder',
		writers: ['Frank Miller', 'Zack Snyder']
	}
};

var movieSchema = {
	title: { _rules: { type: 'string' } },
	crew: {
		director: { _rules: { type: 'string' } },
		writers: { _rules: { type: 'array', arrayType: 'string' } }
	}
};

var error = stefie(movie, movieSchema);

if (error != null) {
	console.log(error);
}

The _rules Object

Add all the rules that apply to a property in the _rules object in the schema.

var schema = {
	title: { _rules: { type: 'string' } },
	rating: { _rules: { type: 'number', required: true, null: false, min: 1, max: 10 } }
};

The Return Object

If there are no errors, stefie() returns null.

If there are errors, she returns an object with each property that failed validation and the reason why.

var movie2 = {
	title: 300,
	crew: {
		director: 'Zack Snyder',
		writers: 'Frank Miller, Zack Snyder'
	}
};

var error = stefie(movie2, movieSchema);

if (error != null) {
	console.log(error);
}

Output:

{
	title: 'Invalid type',
	crew: {
		writers: 'Invalid type'
	}
}

Rules

The following are keys you can use in the _rules object in your schema.

Rule precedence: If you have required and/or null rules, required will be evaluated first, then null, then any other rule.

Rule skip: Rules will not be evaluated if the property value is undefined. The exception is the required rule.

required

Data type: boolean

If true, property must be defined. If false, property can be undefined.

var schema = {
	title: { _rules: { required: true } }
};

Note: Setting this rule to false is logically the same as not using it at all.

null

Data type: boolean

If true, property can be null. If false, property cannot be null.

var schema = {
	rating: { _rules: { null: true } }
};

Note: required and null rules can coexist together.

type

Data type: string

Checks if property is of the specified type.

Possible values	Notes
array
boolean
date	Checks if property is a JavaScript Date object
dateString	Checks if property can be parsed with Date.parse()
jsonString	Checks if property can be parsed with JSON.parse()
number
numberString
object
objectId	Checks if property is a MongoDB ObjectID object
objectIdString	Checks if property is a valid MongoDB ObjectID string
string

var schema = {
	rating: { _rules: { type: 'number' } }
};

arrayType

Data type: string

Checks if an array's elements are of the specified type.

See type for possible values.

var schema = {
	writers: { _rules: { type: 'array', arrayType: 'string' } }
};

min

Data type: number

Checks if property is equal to or greater than the specified number.

var schema = {
	rating: { _rules: { type: 'number', min: 1 } }
};

max

Data type: number

Checks if property is equal to or less than the specified number.

var schema = {
	rating: { _rules: { type: 'number', max: 10 } }
};

minLength

Data type: number

Checks if array/string has a length equal to or greater than the specified number.

var schema = {
	name: { _rules: { type: 'string', minLength: 1 } },
	writers: { _rules: { type: 'array', arrayType: 'string', minLength: 1 } }
};

maxLength

Data type: number

Checks if array/string has a length equal to or less than the specified number.

var schema = {
	name: { _rules: { type: 'string', maxLength: 100 } },
	writers: { _rules: { type: 'array', arrayType: 'string', maxLength: 10 } }
};

enum

Data type: array

If property is a single-value, checks if it is one of the enumerated values. If property is an array, checks if each of its elements is one of the enumerated values.

var schema = {
	director: { _rules: { type: 'string', enum: ['Zack Snyder', 'JJ Abrams'] } },
	cast: { _rules: { type: 'array', enum: ['Gerald Butler', 'Lena Headey', 'Michael Fassbender'] } }
};

regex

Data type: regular expression

Checks if property matches the specified regular expression.

var schema = {
	email: { _rules: { regex: /.+@.+/ } }
};

Custom Validators

You can add your own custom validator functions to stefie, and use it in the _rules object in your schema.

stefie.add(rule, fn)

Arguments:

1. rule (string): Name of the rule
2. fn (function): Validator function

The validator function must have a signature of function(val, ruleVal) where val is the value of the property of the object we are validating and ruleVal is the value of the rule.

var fn = function(val, ruleVal) {
	return (val !== ruleVal ? null : 'Value is disallowed');
};

stefie.add('disallow', fn);

var person = {
	name: 'Stranger'
};

var error = stefie(person,  {
	name: { _rules: { type: 'string', disallow: 'Stranger' } }
});

console.log(error);

Output:

{
	name: 'Value is disallowed'
}

stefie.remove(rule)

Removes a validator. Cannot remove required and null.

Arguments:

1. rule (string): Name of the rule

stefie.remove('disallow');

Test

To run the test cases, cd into the stefie directory then do:

npm test

Author: Harry Lee