schema-inspector

!Lint workflow
!CodeQL workflow
!Test workflow


Schema-Inspector is a powerful tool to sanitize and validate JS objects.
It's designed to work both client-side and server-side and to be scalable with allowing asynchronous and synchronous calls.

See a live example:

Installation

$3

npm install schema-inspector

$3

Bower uses have reported success using the library this way, using bower overrides in bower.json.

!image

Bower is not officially-supported as a build tool and references to it will be removed from the repository in versions 3.0.0+.

Comparison with JSON Schema

schema-inspector is not compatable with JSON Schema. They are two different ways to validate data.
However, the main difference is that schema-inspector supports sanitization of data.

Notable changelogs

$3

To fix a security vulnerability in the 1.x.x email Regex expression used, a new Regex expression was used which may be
less flexible than the expression used in 1.x.x. Therefore, version 2.0.0 was released with this new expression. It's
highly-recommended to upgrade to this new version after testing it.

If you need the old, insecure behavior, use version 1.x.x or use the custom validation function feature for your field
and perform email address validation any way you like.

$3

The email address regular expression was changed again in this version, this time to the new approach towards email address validation that the library will use from now on. For details, see How email address validation works.

How it looks like

Click to see it live!

Usage

``javascript
var inspector = require('schema-inspector');

// Data that we want to sanitize and validate
var data = {
firstname: 'sterling ',
lastname: ' archer',
jobs: 'Special agent, cocaine Dealer',
email: 'NEVER!',
};

// Sanitization Schema
var sanitization = {
type: 'object',
properties: {
firstname: { type: 'string', rules: ['trim', 'title'] },
lastname: { type: 'string', rules: ['trim', 'title'] },
jobs: {
type: 'array',
splitWith: ',',
items: { type: 'string', rules: ['trim', 'title'] },
},
email: { type: 'string', rules: ['trim', 'lower'] },
},
};
// Let's update the data
inspector.sanitize(sanitization, data);
/*
data is now:
{
firstname: 'Sterling',
lastname: 'Archer',
jobs: ['Special Agent', 'Cocaine Dealer'],
email: 'never!'
}
*/

// Validation schema
var validation = {
type: 'object',
properties: {
firstname: { type: 'string', minLength: 1 },
lastname: { type: 'string', minLength: 1 },
jobs: {
type: 'array',
items: { type: 'string', minLength: 1 },
},
email: { type: 'string', pattern: 'email' },
},
};
var result = inspector.validate(validation, data);
if (!result.valid)
console.log(result.format());
/*
Property @.email: must match [email], but is equal to "never!"
*/
`

Tips: it's recommended to use one schema for the sanitization and another for the validation,

In the browser

`html



`

In the example below, the inspector variable will be used. For the client-side use SchemaInspector instead of inspector.

Documentation

$3

* type
* optional
* pattern
* minLength, maxLength, exactLength
* lt, lte, gt, gte, eq, ne
* multipleOf
* someKeys
* strict
* exec
* properties
* items
* alias
* error
* code

$3

* type
* def
* optional
* rules
* min, max
* minLength, maxLength
* strict
* exec
* properties
* items

$3

* punctual use
* extension
* context

$3

* How to

$3

* Benjamin Gressier (major contributor of this awesome module)

Validation

type

* type: string, array of string.
* usable on: any.
* possible values
* string
* number
* integer
* boolean
* null
* date (instanceof Date), you can use the validDate: true to check if the date is valid
object (typeof element === 'object') Note: array, null, or dates don't match the object type*
* array (constructor === Array)
* A function (candidate isinstance)
* any (it can be anything)

Allow to check property type. If the given value is incorrect, then type is not
checked.

$3

`javascript
var inspector = require('schema-inspector');

function Class() {}

var schema = {
type: 'object',
properties: {
lorem: { type: 'number' },
ipsum: { type: 'any' },
dolor: { type: ['number', 'string', 'null'] },
sit: { type: Class },
},
};

var c1 = {
lorem: 12,
ipsum: 'sit amet',
dolor: 23,
sit: new Class(),
};
var c2 = {
lorem: 12,
ipsum: 34,
dolor: 'sit amet',
sit: new Class(),
};
var c3 = {
lorem: 12,
ipsum: ['sit amet'],
dolor: null,
sit: new Class(),
};
var c4 = {
lorem: '12',
ipsum: 'sit amet',
dolor: new Date(),
sit: {},
};

inspector.validate(schema, c1); // Valid
inspector.validate(schema, c2); // Valid
inspector.validate(schema, c3); // Valid
inspector.validate(schema, c4); // Invalid: @.lorem must be a number, @dolor must be a number, a string or null, @.sit must be an instance of Class, but is object
`

---------------------------------------

optional

* type: boolean.
* default: false.
* usable on: any.

This field indicates whether or not property has to exist.

#### Example

`javascript
var inspector = require('Roadspector');

var schema1 = {
type: 'object',
properties: {
lorem: { type: 'any', optional: true },
},
};

var schema2 = {
type: 'object',
properties: {
lorem: { type: 'any', optional: false }, // default value
},
};

var c1 = { lorem: 'ipsum' };
var c2 = {};

inspector.validate(schema1, c1); // Valid
inspector.validate(schema1, c2); // Valid
inspector.validate(schema2, c1); // Valid
inspector.validate(schema2, c2); // Invalid: "@.lorem" is missing and not optional
`

---------------------------------------

uniqueness

* type: boolean.
* default: false.
* usable on: array, string.

If true, then we ensure no element in candidate exists more than once.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'array',
uniqueness: true,
};

var c1 = [12, 23, 34, 45];
var c2 = [12, 23, 34, 12];

inspector.validate(schema, c1); // Valid
inspector.validate(schema, c2); // Invalid: 12 exists twice in @.
`

---------------------------------------

pattern

* type: string, RegExp object, array of string and RegExp.
* usable on: string.
* Possible values as a string: void, url, date-time, date,
coolDateTime, time, color, email, numeric, integer, decimal, v4uuid,
alpha, alphaNumeric, alphaDash, javascript, upperString, lowerString.

Ask Schema-Inspector to check whether or not a given matches provided patterns.
When a pattern is a RegExp, it directly test the string with it. When it's a
string, it's an alias of a built-in RegExp that the library supports. For example, using the string email causes the built-in RegExp for email addresses to be used.

How email address validation works

It is a very flexible regular expression, so that the library is only designed to catch obvious mistakes a user might make in the front end of a system that would have a 100% chance to cause email delivery to fail. An exception is made to forbid email addresses that lack a domain (used only by internal systems). It is based on the recommended regular expression posted on www.regular-expressions.info, modified to allow lowercase alphabetic characters too.

You should perform more thorough checking of email addresses that involves checking whether delivery to the email address would succeed or fail, from your server side code. This library should only be used as basic front end validation for user convenience (e.g. an error displayed in the front end before they submit a form vs. a system failure that may not make it clear to them what went wrong).

If you want to validate strings more strictly than this, you should use your own custom regular expression instead of the email pattern.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema1 = {
type: 'array',
items: { type: 'string', pattern: /^[A-C]/ },
};

var c1 = ['Alorem', 'Bipsum', 'Cdolor', 'DSit amet'];

var schema2 = {
type: 'array',
items: { type: 'string', pattern: 'email' },
};

var c2 = ['lorem@ipsum.com', 'dolor@sit.com', 'amet@consectetur'];

inspector.validate(schema1, c1); // Invalid: @[3] ('DSit amet') does not match /^[A-C]/
inspector.validate(schema2, c2); // Invalid: @[2] ('amet@consectetur') does not match "email" pattern.
`

---------------------------------------

minLength, maxLength, exactLength

* type: integer.
* usable on: array, string.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'object',
properties: {
lorem: { type: 'string', minLength: 4, maxLength: 8 },
ipsum: { type: 'array', exactLength: 6 },
},
};
var c1 = {
lorem: '12345',
ipsum: [1, 2, 3, 4, 5, 6],
};

var c2 = {
lorem: '123456789',
ipsum: [1, 2, 3, 4, 5],
};

inspector.validate(schema, c1); // Valid
inspector.validate(schema, c2); // Invalid: @.lorem must have a length between 4 and 8 (here 9)
// and @.ipsum must have a length of 6 (here 5)
`

---------------------------------------

lt, lte, gt, gte, eq, ne

* type: number (string, number and boolean for eq).
* usable on: number (string, number and boolean for eq).

Check whether comparison is true:

* lt: <
* lte: <=
* gt: >
* gte: >=
* eq: ===
* ne: !==

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'object',
properties: {
lorem: { type: 'number', gt: 0, lt: 5 }, // Between ]0; 5[
ipsum: { type: 'number', gte: 0, lte: 5 }, // Between [0; 5]
dolor: { type: 'number', eq: [0, 3, 6, 9] }, // Equal to 0, 3, 6 or 9
sit: { type: 'number', ne: [0, 3, 6, 9] }, // Not equal to 0, 3, 6 nor 9
},
};

var c1 = { lorem: 3, ipsum: 0, dolor: 6, sit: 2 };
var c2 = { lorem: 0, ipsum: -1, dolor: 5, sit: 3 };

inspector.validate(schema, c1); // Valid
inspector.validate(schema, c2); // Invalid
`

---------------------------------------

multipleOf

* type: number
* usable on: number, array

Check whether the candidate is a multiple of the provided option. If the candidate is an array of numbers, it performs this validation on each number in the array.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'number',
multipleOf: 2 // Even
};

var c1 = 100;
var c2 = 73;

inspector.validate(schema, c1); // Valid
inspector.validate(schema, c2); // Invalid: 73 is not divisible by 2
`

---------------------------------------

someKeys

* type: array of string.
* usable on: object.

Check whether one of the given keys exists in object (useful when they are
optional).

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'object',
someKeys: ['lorem', 'ipsum'],
properties: {
lorem: { type: 'any', optional: true },
ipsum: { type: 'any', optional: true },
dolor: { type: 'any' },
},
};

var c1 = { lorem: 0, ipsum: 1, dolor: 2 };
var c2 = { lorem: 0, dolor: 2 };
var c3 = { dolor: 2 };

inspector.validate(schema, c1); // Valid
inspector.validate(schema, c2); // Valid
inspector.validate(schema, c3); // Invalid: Neither @.lorem nor @.ipsum is in c3.
`

---------------------------------------

strict

* type: boolean.
* default: false.
* usable on: object.

Only keys provided in field "properties" may exist in the object. Strict will be ignored if properties has the special key '*'.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'object',
strict: true,
properties: {
lorem: { type: 'any' },
ipsum: { type: 'any' },
dolor: { type: 'any' },
},
};

var c1 = { lorem: 0, ipsum: 1, dolor: 2 };
var c2 = { lorem: 0, ipsum: 1, dolor: 2, sit: 3 };

inspector.validate(schema, c1); // Valid
inspector.validate(schema, c2); // Invalid: @.sit should not exist.
`

---------------------------------------

exec

* type: function, array of function.
* usable on: any.

Custom checker =). "exec" functions take two three parameter
(schema, post [, callback]). To report an error, use this.report([message], [code]).
Very useful to make some custom validation.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'object',
properties: {
lorem: {
type: 'number',
exec: function (schema, post) {
// here schema === schema.properties.lorem and post === @.lorem
if (post === 3) {
// As soon as this.report() is called, candidate is not valid.
this.report('must not equal 3 =('); // Ok...it's exactly like "ne: 3"
}
},
},
},
};

var c1 = { lorem: 2 };
var c2 = { lorem: 3 };

inspector.validate(schema, c1); // Valid
inspector.validate(schema, c2); // Invalid: "@.lorem must not equal 3 =(".
`

---------------------------------------

properties

* type: object.
* usable on: object.

For each property in the field "properties", whose value must be a schema,
validation is called deeper in object.

The special property '*' is validated against any properties not specifically listed.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'object',
properties: {
lorem: {
type: 'object',
properties: {
ipsum: {
type: 'object',
properties: {
dolor: { type: 'string' },
},
},
},
},
consectetur: { type: 'string' },
'*': { type: 'integer' },
},
};

var c1 = {
lorem: {
ipsum: {
dolor: 'sit amet',
},
},
consectetur: 'adipiscing elit',
adipiscing: 12,
};
var c2 = {
lorem: {
ipsum: {
dolor: 12,
},
},
consectetur: 'adipiscing elit',
};

inspector.validate(schema, c1); // Valid
inspector.validate(schema, c2); // Invalid: @.lorem.ipsum.dolor must be a string.
`

---------------------------------------

items

* type: object, array of object.
* usable on: array.

Allow to apply schema validation for each element in an array. If it's an
object, then it's a schema which will be used for all the element. If it's an
array of object, then it's an array of schema and each element in an array will
be checked with the schema which has the same position in the array.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema1 = {
type: 'array',
items: { type: 'number' },
};

var schema2 = {
type: 'array',
items: [{ type: 'number' }, { type: 'number' }, { type: 'string' }],
};

var c1 = [1, 2, 3];
var c2 = [1, 2, 'string!'];

inspector.validate(schema1, c1); // Valid
inspector.validate(schema1, c2); // Invalid: @[2] must be a number.
inspector.validate(schema2, c1); // Invalid: @[2] must be a string.
inspector.validate(schema2, c2); // Valid
`

---------------------------------------

alias

* type: string.
* usable on: any.

Allow to display a more explicit property name if an error is encounted.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema1 = {
type: 'object',
properties: {
_id: { type: 'string' },
},
};

var schema2 = {
type: 'object',
properties: {
_id: { alias: 'id', type: 'string' },
},
};

var c1 = { _id: 1234567890 };

var r1 = inspector.validate(schema1, c1);
var r2 = inspector.validate(schema2, c1);
console.log(r1.format()); // Property @._id: must be string, but is number
console.log(r2.format()); // Property id (@._id): must be string, but is number
`

---------------------------------------

error

* type: string.
* usable on: any.

This field contains a user sentence for displaying a more explicit message if
an error is encounted.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema1 = {
type: 'object',
properties: {
_id: { type: 'string' },
},
};

var schema2 = {
type: 'object',
properties: {
_id: { type: 'string', error: 'must be a valid ID.' },
},
};

var c1 = { _id: 1234567890 };

var r1 = inspector.validate(schema1, c1);
var r2 = inspector.validate(schema2, c1);
console.log(r1.format()); // Property @._id: must be string, but is number.
console.log(r2.format()); // Property @._id: must be a valid ID.
`

---------------------------------------

code

* type: string.
* usable on: any.

This field contains a user code for displaying a more uniform system to personnalize error message.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema1 = {
type: 'object',
properties: {
_id: { type: 'string' },
},
};

var schema2 = {
type: 'object',
properties: {
_id: { type: 'string', code: 'id-format' },
},
};

var c1 = { _id: 1234567890 };

var r1 = inspector.validate(schema1, c1);
var r2 = inspector.validate(schema2, c1);
console.log(r1.error[0].code); // null
console.log(r2.error[0].code); // 'id-format'
`

Sanitization

type

* type: string.
* usable on: any.
* possible values
* number
* integer
* string
* boolean
* date (constructor === Date)
* object (constructor === Object)
* array (constructor === Array)

Cast property to the given type according to the following description:

* to number from:
* string (ex: "12.34" -> 12.34)
!sanitization string to number
* date (ex: new Date("2014-01-01") -> 1388534400000)
!sanitization string to number
* to integer from:
* number
* 12.34 -> 12
* string
* "12.34" -> 12
* boolean
* true -> 1
* false -> 0
* date
* new Date("2014-01-01") -> 1388534400000
* to string from:
* boolean
* true -> "true"
* number
* 12.34 -> "12.34"
* integer
* 12 -> "12"
* date
* new Date("2014-01-01") -> "Wed Jan 01 2014 01:00:00 GMT+0100 (CET)"
* array
* [12, 23, 44] -> '12,34,45'
* To join with a custom string, use joinWith key (example: { type: "string", joinWith: "|" } will transform [12, 23, 44] to "12|23|44").
* to date from:
* number / integer
* 1361790386000 -> Wed Jan 01 2014 01:00:00 GMT+0100 (CET)
* string
* "2014-01-01 -> Wed Jan 01 2014 01:00:00 GMT+0100 (CET)
* "Wed Jan 01 2014 01:00:00 GMT+0100 (CET)" -> Wed Jan 01 2014 01:00:00 GMT+0100 (CET)
* to object from:
* string
* '{"love":"open source"}' -> { love: "open source" }
* to array from:
* string ("one,two,three" -> ["one", "two", "three"], '[1,"two",{"three":true}]' -> [ 1, 'two', { three: true } ])
* anything except undefined and array (23 -> [ 23 ])
To split with a custom string (other than ","), use the key splitWith (example: { type: "array", splitWith: "|"" } will transform "one|two|three" to ["one", "two", "three"]).

$3

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'array',
items: { type: 'string' },
};

var c = [12.23, -34, true, false, 'true', 'false', [123, 234, 345], { obj: "yes" }];

var r = inspector.sanitize(schema, c);
/*
r.data: [ '12.23', '-34', 'true', 'false', 'true', 'false', '123,234,345', '{"obj":"yes"}' ]
*/
`

---------------------------------------

def

* type: any.
* usable on: any.

Define default value if property does not exist, or if type casting is to fail
because entry type is not valid (cf type).

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'object',
properties: {
lorem: { type: 'number', def: 10 },
ipsum: { type: 'string', def: 'NikitaJS', optional: false },
dolor: { type: 'string' },
},
};

var c = {
lorem: [12, 23], // convertion to number is about to fail
// (array -> number is not possible)
// ipsum is not privided
dolor: 'sit amet', // "dolor" is already a string
};

var r = inspector.sanitize(schema, c);
/*
r.data: {
lorem: 10,
ipsum: 'NikitaJS',
dolor: 'sit amet'
}
*/
`

---------------------------------------

optional

* type: boolean.
* default: true.
* usable on: any.

Property is set to schema.def if not provided and if optional is false.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'object',
properties: {
lorem: { type: 'number', optional: false, def: 12 },
ipsum: { type: 'string', optional: true, def: 23 },
dolor: { type: 'string', def: 'NikitaJS', def: 34 }, // (optional: true)
},
};

var c = {};

var r = inspector.sanitize(schema, c);
/*
r.data: {
lorem: 12 // Only lorem is set to 12 because it is not optional.
}
*/
`

---------------------------------------

rules

* type: string, array of string.
* usable on: string.
* possible values:
* upper: Every character will be changed to uppercase.
* lower: Every character will be changed to lowercase.
title: For each word (/\S/g), first letter will be changed to uppercase, and the rest to lowercase.
* capitalize: Only the first letter of the string will be changed to uppercase, the rest to lowercase.
* ucfirst: Only the first letter of the string will be changed to uppercase, the rest is not modified.
* trim: Remove extra spaces.

Apply the given rule to a string. If several rules are given (array), then they
are applied in the same order than in the array.

!sanitization min/max

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'object',
properties: {
lorem: { type: 'string', rules: 'upper' },
ipsum: { type: 'string', rules: ['trim', 'title'] },
},
};

var c = {
lorem: ' tHiS is sParTa! ',
ipsum: ' tHiS is sParTa! ',
};

var r = inspector.sanitize(schema, c);
/*
r.data: {
lorem: ' THIS IS SPARTA! ',
ipsum: 'This Is Sparta!' // has been trimed, then titled
}
*/
`

---------------------------------------

min, max

* type: string, number.
* usable on: string, number.

Define minimum and maximum value for a property. If it's less than minimum,
then it's set to minimum. If it's greater than maximum, then it's set to
maximum.

!sanitization min/max

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'array',
items: { type: 'number', min: 10, max: 20 },
};

var c = [5, 10, 15, 20, 25];

var r = inspector.sanitize(schema, c);
/*
r.data: [10, 10, 15, 20, 20]
c[0] (5) was less than min (10), so it's been set to 10.
c[4] (25) was greater than max (20), so it's been set to 20.
*/
`

---------------------------------------

minLength, maxLength

* type: integer.
* usable on: string.

Adjust string length to the given number.

__TODO:__ We must be able to choose which character we want to fill the string with.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'array',
items: { type: 'string', minLength: 8, maxLength: 11 },
};

var c = ['short', 'mediumSize', 'tooLongForThisSchema'];

var r = inspector.sanitize(schema, c);
/*
r.data: ['short---', 'mediumSize', 'tooLongForT']
*/
`

---------------------------------------

strict

* type: boolean.
* default: false.
* usable on: any.

Only key provided in field "properties" will exist in object, others will be deleted.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'object',
strict: true,
properties: {
good: { type: 'string' },
},
};

var c = {
good: 'yes',
bad: 'nope',
};

var r = inspector.sanitize(schema, c);
/*
r.data: {
good: 'yes'
}
*/
`

---------------------------------------

exec

* type: function, array of functions.
* usable on: any.

Custom checker =). "exec" functions take two three parameter
(schema, post [, callback]), and must return the new value. To report an
sanitization, use this.report([message]). Very useful to make some custom
sanitization.

__NB:__ If you don't want to return a differant value, simply return post,
do not return nothing (if you do so, the new value will be undefined).

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'array',
items: {
type: 'string',
exec: function (schema, post) {
if (typeof post === 'string' && !/^nikita$/i.test(post)) {
this.report();
return '_INVALID_';
}
return post;
},
},
};

var c = ['Nikita', 'lol', 'NIKITA', 'thisIsGonnaBeSanitized!'];

var r = inspector.sanitize(schema, c);
/*
r.data: [ 'Nikita', '_INVALID_', 'NIKITA', '_INVALID_' ]
*/
`

---------------------------------------

properties

* type: object.
* usable on: object.

Work the same way as validation "properties".

---------------------------------------

items

* type: object, array of object.
* usable on: array.

Work the same way as validation "items".

Custom fields

punctual use

When you need to use the same function in exec field several time, instead of
saving the function and declaring exec several times, just use custom field.
First you have to provide a hash containing a function for each custom field you
want to inject. Then you can call them in your schema with $"your field name".
For example if you
provide a custom field called "superiorMod", you can access it with name
"$superiorMod".


#### Example

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'object',
properties: {
lorem: { type: 'number', $divisibleBy: 5 },
ipsum: { type: 'number', $divisibleBy: 3 },
},
};

var custom = {
divisibleBy: function (schema, candidate) {
var dvb = schema.$divisibleBy;
if (candidate % dvb !== 0) {
this.report('must be divisible by ' + dvb);
}
},
};

var c = {
lorem: 10,
ipsum: 8,
};
inspector.validate(schema, candidate, custom); // Invalid: "@.ipsum must be divisible by 3"
`

---------------------------------------

extension

Sometime you want to use a custom field everywhere in your program, so you may
extend Schema-Inspector to do so. Just call the method
_inspector.Validation.extend(customFieldObject)_ or
_inspector.Sanitization.extend(customFieldObject)_. If you want to reset, simply call
_inspector.Validation.reset()_ or _inspector.Sanitization.reset()_. You also can remove a
specific field by calling _inspector.Validation.remove(field)_ or
_inspector.Sanitization.remove(field)_.

#### Example

`javascript
var inspector = require('schema-inspector');

var custom = {
divisibleBy: function (schema, candidate) {
var dvb = schema.$divisibleBy;
if (candidate % dvb !== 0) {
this.report('must be divisible by ' + dvb);
}
},
};

var schema = {
type: 'object',
properties: {
lorem: { type: 'number', $divisibleBy: 5 },
ipsum: { type: 'number', $divisibleBy: 3 },
},
};

inspector.Validation.extend(custom);

var candidate = {
lorem: 10,
ipsum: 8,
};

inspector.validate(schema, candidate);
/*
As you can see, no more object than schema and candidate has been provided.
Therefore we can use $divisibleBy everywhere in all schemas, for each
inspector.validate() call.
*/
`

---------------------------------------

Context

Every function you declare as a custom parameter, or with exec field will be
called with a context. This context allows you to access properties, like
this.report() function, but also this.origin, which is equal to the object
sent to inspector.validate() or inspector.sanitize().

#### Example

`javascript
// ...
var schema = { / ... / };
var custom = {
divisibleBy: function (schema, candidate) {
// this.origin === [12, 23, 34, 45]
// ...
},
};
var candidate = [12, 23, 34, 45];
var result = inspector.validate(schema, candidate, custom);
// ...
`

Asynchronous call

$3

All of the examples above used synchronous calls (the simplest). But sometimes you
want to call validation or sanitization asynchronously, in particular with
exec and custom fields. It's pretty simple: To do so, just send a callback
as extra parameter. It takes 2 parameters: error and result. Actually
Schema-Inspector should send back no error as it should not throw any if called
synchronously. But if you want to send back and error in your custom function,
inspection will be interrupted, and you will be able to retrieve it in your
callback.

You also have to declare a callback in your exec or custom function to make
Schema-Inspector call it asynchronously, else it will be call synchronously.
That means you may use exec synchronous function normally even during
and asynchronous call.

#### Example

`javascript
var inspector = require('schema-inspector');

var schema = { / ... / };
var candidate = { / ... / };

inspector.validate(schema, candidate, function (err, result) {
console.log(result.format());
});
`

#### Example with custom field

`javascript
var inspector = require('schema-inspector');

var schema = { / ... / };
var candidate = { / ... / };
var custom = { / ... / };

inspector.validate(schema, candidate, custom, function (err, result) {
console.log(result.format());
});
`

Here is a full example where you may have to use it:

`javascript
var inspector = require('schema-inspector');

var schema = {
type: 'object',
properties: {
lorem: { type: 'number', $divisibleBy: 4 },
ipsum: { type: 'number', $divisibleBy: 5 },
dolor: { type: 'number', $divisibleBy: 0, optional: true },
},
};

var custom = {
divisibleBy: function (schema, candidate, callback) {
// Third parameter is declared:
// Schema-Inspector will wait this function to call this callback to keep running.
var dvb = schema.$divisibleBy;
if (typeof dvb !== 'number' || typeof candidate !== 'number') {
return callback();
}
var self = this;
process.nextTick(function () {
if (dvb === 0) {
return callback(
new Error('Schema error: Divisor must not equal 0')
);
}
var r = candidate / dvb;
if ((r | 0) !== r) {
self.report('should be divisible by ' + dvb);
}
callback();
});
},
};

var candidate = {
lorem: 12,
ipsum: 25,
};

inspector.validate(schema, candidate, custom, function (err, result) {
console.log(result.format());
});
``