Object schema description language and validator for JavaScript objects.
Lead Maintainer: Nicolas Morel
Imagine you run facebook and you want visitors to sign up on the website with real names and not something like l337_p@nda
in the first name field. How would you define the limitations of what can be inputted and validate it against the set rules?
- Example
- Usage
validate(value, schema, [options], [callback])
compile(schema)
assert(value, schema, [message])
any
any.allow(value)
any.valid(value)
- aliases:only
,equal
any.invalid(value)
- aliases:disallow
,not
any.required()
any.optional()
any.forbidden()
any.description(desc)
any.notes(notes)
any.tags(tags)
any.meta(meta)
any.example(value)
any.unit(name)
any.options(options)
any.strict()
any.default(value, [description])
any.concat(schema)
any.when(ref, options)
any.label(name)
any.raw(isRaw)
array
boolean
binary
date
func
number
object
object.keys([schema])
object.min(limit)
object.max(limit)
object.length(limit)
object.pattern(regex, schema)
object.and(peers)
object.nand(peers)
object.or(peers)
object.xor(peers)
object.with(key, peers)
object.without(key, peers)
object.rename(from, to, [options])
object.assert(ref, schema, [message])
object.unknown([allow])
object.type(constructor, [name])
object.requiredKeys(children)
object.optionalKeys(children)
objectId
string
string.insensitive()
string.min(limit, [encoding])
string.max(limit, [encoding])
string.creditCard()
string.length(limit, [encoding])
string.regex(pattern, [name])
string.alphanum()
string.token()
string.email([options])
string.guid()
string.hex()
string.hostname()
string.lowercase()
string.uppercase()
string.trim()
alternatives
ref(key, [options])
This is joi, joi allows you to create blueprints or schemas for JavaScript objects (an object that stores information) to ensure validation of key information.
var Joi = require('joi');
var schema = Joi.object().keys({
username: Joi.string().alphanum().min(3).max(30).required(),
password: Joi.string().regex(/^[a-zA-Z0-9]{3,30}$/),
access_token: [Joi.string(), Joi.number()],
birthyear: Joi.number().integer().min(1900).max(2013),
email: Joi.string().email()
}).with('username', 'birthyear').without('password', 'access_token');
Joi.validate({ username: 'abc', birthyear: 1994 }, schema, function (err, value) { }); // err === null -> valid
The above schema defines the following constraints:
username
- a required string
- must contain only alphanumeric characters
- at least 3 characters long but no more than 30
- must be accompanied by
birthyear
password
- an optional string
- must satisfy the custom regex
- cannot appear together with
access_token
access_token
- an optional, unconstrained string or number
birthyear
- an integer between 1900 and 2013
email
- a valid email address string
Usage is a two steps process. First, a schema is constructed using the provided types and constraints:
var schema = {
a: Joi.string()
};
Note that joi schema objects are immutable which means every additional rule added (e.g. .min(5)
) will return a
new schema object.
Then the value is validated against the schema:
Joi.validate({ a: 'a string' }, schema, function (err, value) { });
If the value is valid, null
is returned, otherwise an Error
object.
The schema can be a plain JavaScript object where every key is assigned a joi type, or it can be a joi type directly:
var schema = Joi.string().min(10);
If the schema is a joi type, the schema.validate(value, callback)
can be called directly on the type. When passing a non-type schema object,
the module converts it internally to an object() type equivalent to:
var schema = Joi.object().keys({
a: Joi.string()
});
When validating a schema:
- Keys are optional by default.
- Strings are utf-8 encoded by default.
- Rules are defined in an additive fashion and evaluated in order after whitelist and blacklist checks.
Validates a value using the given schema and options where:
value
- the value being validated.schema
- the validation schema. Can be a joi type object or a plain object where every key is assigned a joi type object.options
- an optional object with the following optional keys:abortEarly
- whentrue
, stops validation on the first error, otherwise returns all the errors found. Defaults totrue
.convert
- whentrue
, attempts to cast values to the required types (e.g. a string to a number). Defaults totrue
.allowUnknown
- whentrue
, allows object to contain unknown keys which are ignored. Defaults tofalse
.skipFunctions
- whentrue
, ignores unknown keys with a function value. Defaults tofalse
.stripUnknown
- whentrue
, unknown keys are deleted (only when value is an object). Defaults tofalse
.language
- overrides individual error messages, when'label'
is set, it overrides the key name in the error message. Defaults to no override ({}
).presence
- sets the default presence requirements. Supported modes:'optional'
,'required'
, and'forbidden'
. Defaults to'optional'
.context
- provides an external data set to be used in references. Can only be set as an external option tovalidate()
and not usingany.options()
.
callback
- the optional synchronous callback method using the signaturefunction(err, value)
where:err
- if validation failed, the error reason, otherwisenull
.value
- the validated value with any type conversions and other modifiers applied (the input is left unchanged).value
can be incomplete if validation failed andabortEarly
istrue
. If callback is not provided, then returns an object with error and value properties.
var schema = {
a: Joi.number()
};
var value = {
a: '123'
};
Joi.validate(value, schema, function (err, value) { });
// err -> null
// value.a -> 123 (number, not string)
// or
var result = Joi.validate(value, schema);
// result.error -> null
// result.value -> { "a" : 123 }
Converts literal schema definition to joi schema object (or returns the same back if already a joi schema object) where:
schema
- the schema definition to compile.
var definition = ['key', 5, { a: true, b: [/^a/, 'boom'] }];
var schema = Joi.compile(definition);
// Same as:
var schema = Joi.alternatives().try([
Joi.string().valid('key'),
Joi.number().valid(5),
Joi.object().keys({
a: Joi.boolean().valid(true),
b: Joi.alternatives().try([
Joi.string().regex(/^a/),
Joi.string().valid('boom')
])
})
]);
Validates a value against a schema and throws if validation fails where:
value
- the value to validate.schema
- the schema object.message
- optional message sting prefix added in front of the error message.
Joi.assert('x', Joi.number());
Generates a schema object that matches any data type.
var any = Joi.any();
any.validate('a', function (err, value) { });
Whitelists a value where:
value
- the allowed value which can be of any type and will be matched against the validated value before applying any other rules.value
can be an array of values, or multiple values can be passed as individual arguments.value
supports references.
Note that this whitelist of allowed values is in addition to any other permitted values.
To create an exclusive whitelist of values, see any.valid(value)
.
var schema = {
a: Joi.any().allow('a'),
b: Joi.any().allow('b', 'B'),
c: Joi.any().allow(['c', 'C'])
};
Adds the provided values into the allowed whitelist and marks them as the only valid values allowed where:
value
- the allowed value which can be of any type and will be matched against the validated value before applying any other rules.value
can be an array of values, or multiple values can be passed as individual arguments.value
supports references.
var schema = {
a: Joi.any().valid('a'),
b: Joi.any().valid('b', 'B'),
c: Joi.any().valid(['c', 'C'])
};
Blacklists a value where:
value
- the forbidden value which can be of any type and will be matched against the validated value before applying any other rules.value
can be an array of values, or multiple values can be passed as individual arguments.value
supports references.
var schema = {
a: Joi.any().invalid('a'),
b: Joi.any().invalid('b', 'B'),
c: Joi.any().invalid(['c', 'C'])
};
Marks a key as required which will not allow undefined
as value. All keys are optional by default.
var schema = Joi.any().required();
Marks a key as optional which will allow undefined
as values. Used to annotate the schema for readability as all keys are optional by default.
var schema = Joi.any().optional();
Marks a key as forbidden which will not allow any value except undefined
. Used to explicitly forbid keys.
var schema = {
a: Joi.any().forbidden()
};
Annotates the key where:
desc
- the description string.
var schema = Joi.any().description('this key will match anything you give it');
Annotates the key where:
notes
- the notes string or array of strings.
var schema = Joi.any().notes(['this is special', 'this is important']);
Annotates the key where:
tags
- the tag string or array of strings.
var schema = Joi.any().tags(['api', 'user']);
Attaches metadata to the key where:
meta
- the meta object to attach.
var schema = Joi.any().meta({ index: true });
Annotates the key where:
value
- an example value.
If the example fails to pass validation, the function will throw.
var schema = Joi.string().min(4).example('abcd');
Annotates the key where:
name
- the unit name of the value.
var schema = Joi.number().unit('milliseconds');
Overrides the global validate()
options for the current key and any sub-key where:
options
- an object with the same optional keys asJoi.validate(value, schema, options, callback)
.
var schema = Joi.any().options({ convert: false });
Sets the options.convert
options to false
which prevent type casting for the current key and any child keys.
var schema = Joi.any().strict();
Sets a default value if the original value is undefined where:
value
- the value.value
supports references.value
may also be a function which returns the default value. Ifvalue
is specified as a function that accepts a single parameter, that parameter will be a context object that can be used to derive the resulting value. This clones the object however, which incurs some overhead so if you don't need access to the context define your method so that it does not accept any parameters.
Note that if value
is an object, any changes to the object after default()
is called will change the reference
and any future assignment.
Additionally, when specifying a method you must either have a description
property on your method or the second parameter is required.
var generateUsername = function (context) {
return context.firstname.toLowerCase() + '-' + context.lastname.toLowerCase();
};
generateUsername.description = 'generated username';
var schema = {
username: Joi.string().default(generateUsername),
firstname: Joi.string(),
lastname: Joi.string(),
created: Joi.date().default(Date.now, 'time of creation'),
status: Joi.string().default('registered')
};
Joi.validate({
firstname: 'Jane',
lastname: 'Doe'
}, function (err, value) {
// value.status === 'registered'
// value.username === 'jane-doe'
// value.created will be the time of validation
});
Returns a new type that is the result of adding the rules of one type to another where:
schema
- a joi type to merge into the current schema. Can only be of the same type as the context type orany
.
var a = Joi.string().valid('a');
var b = Joi.string().valid('b');
var ab = a.concat(b);
Converts the type into an alternatives
type where the conditions are merged into the type definition where:
ref
- the key name or reference.options
- an object with:is
- the required condition joi type.then
- the alternative schema type if the condition is true. Required ifotherwise
is missing.otherwise
- the alternative schema type if the condition is false. Required ifthen
is missing.
var schema = {
a: Joi.any().valid('x').when('b', { is: 5, then: Joi.valid('y'), otherwise: Joi.valid('z') }),
b: Joi.any()
};
Alternatively, if you want to specify a specific type such as string
, array
, etc, you can do so like this:
var schema = {
a: Joi.valid('a', 'b', 'other'),
other: Joi.string()
.when('a', { is: 'other', then: Joi.required() }),
};
Overrides the key name in error messages.
name
- the name of the key.
var schema = {
first_name: Joi.string().label('First Name')
};
Outputs the original untouched value instead of the casted value.
isRaw
- whether to enable raw mode or not. Defaults to true.
var schema = {
timestamp: Joi.date().format('YYYYMMDD').raw()
};
Generates a schema object that matches an array data type. Note that undefined values inside arrays are not allowed by default but can be by using sparse()
.
Supports the same methods of the any()
type.
var array = Joi.array().includes(Joi.string().valid('a', 'b'));
array.validate(['a', 'b', 'a'], function (err, value) { });
Allow this array to be sparse. enabled
can be used with a falsy value to go back to the default behavior.
var schema = Joi.array().sparse(); // undefined values are now allowed
schema = schema.sparse(false); // undefined values are now denied
Allow single values to be checked against rules as if it were provided as an array.
enabled
can be used with a falsy value to go back to the default behavior.
var schema = Joi.array().includes(Joi.number()).single();
schema.validate([4]); // returns `{ error: null, value: [ 4 ] }`
schema.validate(4); // returns `{ error: null, value: [ 4 ] }`
List the types allowed for the array values where:
type
- a joi schema object to validate each array item against.type
can be an array of values, or multiple values can be passed as individual arguments.
var schema = Joi.array().includes(Joi.string(), Joi.number());
List the types forbidden for the array values where:
type
- a joi schema object to validate each array item against.type
can be an array of values, or multiple values can be passed as individual arguments.
var schema = Joi.array().excludes(Joi.object());
Specifies the minimum number of items in the array where:
limit
- the lowest number of array items allowed.
var schema = Joi.array().min(2);
Specifies the maximum number of items in the array where:
limit
- the highest number of array items allowed.
var schema = Joi.array().max(10);
Specifies the exact number of items in the array where:
limit
- the number of array items allowed.
var schema = Joi.array().length(5);
Requires the array values to be unique.
Be aware that a deep equality is performed on elements of the array having a type of object
, a performance penalty is to be expected for this kind of operation.
var schema = Joi.array().unique();
Generates a schema object that matches a boolean data type (as well as the strings 'true', 'false', 'yes', and 'no'). Can also be called via bool()
.
Supports the same methods of the any()
type.
var boolean = Joi.boolean();
boolean.validate(true, function (err, value) { });
Generates a schema object that matches a Buffer data type (as well as the strings which will be converted to Buffers).
Supports the same methods of the any()
type.
var schema = Joi.binary();
Sets the string encoding format if a string input is converted to a buffer where:
encoding
- the encoding scheme.
var schema = Joi.binary().encoding('base64');
Specifies the minimum length of the buffer where:
limit
- the lowest size of the buffer.
var schema = Joi.binary().min(2);
Specifies the maximum length of the buffer where:
limit
- the highest size of the buffer.
var schema = Joi.binary().max(10);
Specifies the exact length of the buffer:
limit
- the size of buffer allowed.
var schema = Joi.binary().length(5);
Generates a schema object that matches a date type (as well as a JavaScript date string or number of milliseconds).
Supports the same methods of the any()
type.
var date = Joi.date();
date.validate('12-21-2012', function (err, value) { });
Specifies the oldest date allowed where:
date
- the oldest date allowed.
var schema = Joi.date().min('1-1-1974');
Notes: 'now'
can be passed in lieu of date
so as to always compare relatively to the current date, allowing to explicitly ensure a date is either in the past or in the future.
var schema = Joi.date().min('now');
It can also be a reference to another field.
var schema = Joi.object({
from: Joi.date().required(),
to: Joi.date().min(Joi.ref('from')).required()
});
Specifies the latest date allowed where:
date
- the latest date allowed.
var schema = Joi.date().max('12-31-2020');
Notes: 'now'
can be passed in lieu of date
so as to always compare relatively to the current date, allowing to explicitly ensure a date is either in the past or in the future.
var schema = Joi.date().max('now');
It can also be a reference to another field.
var schema = Joi.object({
from: Joi.date().max(Joi.ref('to')).required(),
to: Joi.date().required()
});
Specifies the allowed date format:
format
- string or array of strings that follow themoment.js
format.
var schema = Joi.date().format('YYYY/MM/DD');
Requires the string value to be in valid ISO 8601 date format.
var schema = Joi.date().iso();
Generates a schema object that matches a function type.
Supports the same methods of the any()
type.
var func = Joi.func();
func.validate(function () {}, function (err, value) { });
Generates a schema object that matches a number data type (as well as strings that can be converted to numbers).
Infinity
and -Infinity
are invalid by default, you can change that behavior by calling allow(Infinity, -Infinity)
.
Supports the same methods of the any()
type.
var number = Joi.number();
number.validate(5, function (err, value) { });
Specifies the minimum value where:
limit
- the minimum value allowed.
var schema = Joi.number().min(2);
Specifies the maximum value where:
limit
- the maximum value allowed.
var schema = Joi.number().max(10);
Specifies that the value must be greater than limit
.
var schema = Joi.number().greater(5);
Specifies that the value must be less than limit
.
var schema = Joi.number().less(10);
Requires the number to be an integer (no floating point).
var schema = Joi.number().integer();
Specifies the maximum number of decimal places where:
limit
- the maximum number of decimal places allowed.
var schema = Joi.number().precision(2);
Specifies that the value must be a multiple of base
:
var schema = Joi.number().multiple(3);
Generates a schema object that matches an object data type (as well as JSON strings that parsed into objects). Defaults to allowing any child key.
Supports the same methods of the any()
type.
var object = Joi.object().keys({
a: Joi.number().min(1).max(10).integer(),
b: 'some string'
});
object.validate({ a: 5 }, function (err, value) { });
Sets or extends the allowed object keys where:
schema
- optional object where each key is assigned a joi type object. Ifschema
is{}
no keys allowed. Ifschema
isnull
orundefined
, any key allowed. Ifschema
is an object with keys, the keys are added to any previously defined keys (but narrows the selection if all keys previously allowed). Defaults to 'undefined' which allows any child key.
var base = Joi.object().keys({
a: Joi.number(),
b: Joi.string()
});
// Validate keys a, b and c.
var extended = base.keys({
c: Joi.boolean()
});
Specifies the minimum number of keys in the object where:
limit
- the lowest number of keys allowed.
var schema = Joi.object().min(2);
Specifies the maximum number of keys in the object where:
limit
- the highest number of object keys allowed.
var schema = Joi.object().max(10);
Specifies the exact number of keys in the object where:
limit
- the number of object keys allowed.
var schema = Joi.object().length(5);
Specify validation rules for unknown keys matching a pattern where:
regex
- a regular expression tested against the unknown key names.schema
- the schema object matching keys much validate against.
var schema = Joi.object({
a: Joi.string()
}).pattern(/\w\d/, Joi.boolean());
Defines an all-or-nothing relationship between keys where if one of the peers is present, all of them are required as well where:
peers
- the key names of which if one present, all are required.peers
can be a single string value, an array of string values, or each peer provided as an argument.
var schema = Joi.object().keys({
a: Joi.any(),
b: Joi.any()
}).and('a', 'b');
Defines a relationship between keys where not all peers can be present at the same time where:
peers
- the key names of which if one present, the others may not all be present.peers
can be a single string value, an array of string values, or each peer provided as an argument.
var schema = Joi.object().keys({
a: Joi.any(),
b: Joi.any()
}).nand('a', 'b');
Defines a relationship between keys where one of the peers is required (and more than one is allowed) where:
peers
- the key names of which at least one must appear.peers
can be a single string value, an array of string values, or each peer provided as an argument.
var schema = Joi.object().keys({
a: Joi.any(),
b: Joi.any()
}).or('a', 'b');
Defines an exclusive relationship between a set of keys where one of them is required but not at the same time where:
peers
- the exclusive key names that must not appear together but where one of them is required.peers
can be a single string value, an array of string values, or each peer provided as an argument.
var schema = Joi.object().keys({
a: Joi.any(),
b: Joi.any()
}).xor('a', 'b');
Requires the presence of other keys whenever the specified key is present where:
key
- the reference key.peers
- the required peer key names that must appear together withkey
.peers
can be a single string value or an array of string values.
Note that unlike object.and()
, with()
creates a dependency only between the key
and each of the peers
, not
between the peers
themselves.
var schema = Joi.object().keys({
a: Joi.any(),
b: Joi.any()
}).with('a', 'b');
Forbids the presence of other keys whenever the specified is present where:
key
- the reference key.peers
- the forbidden peer key names that must not appear together withkey
.peers
can be a single string value or an array of string values.
var schema = Joi.object().keys({
a: Joi.any(),
b: Joi.any()
}).without('a', ['b']);
Renames a key to another name (deletes the renamed key) where:
from
- the original key name.to
- the new key name.options
- an optional object with the following optional keys:alias
- iftrue
, does not delete the old key name, keeping both the new and old keys in place. Defaults tofalse
.multiple
- iftrue
, allows renaming multiple keys to the same destination where the last rename wins. Defaults tofalse
.override
- iftrue
, allows renaming a key over an existing key. Defaults tofalse
.
Keys are renamed before any other validation rules are applied.
var object = Joi.object().keys({
a: Joi.number()
}).rename('b', 'a');
object.validate({ b: 5 }, function (err, value) { });
Verifies an assertion where:
ref
- the key name or reference.schema
- the validation rules required to satisfy the assertion. If theschema
includes references, they are resolved against the object value, not the value of theref
target.message
- optional human-readable message used when the assertion fails. Defaults to 'failed to pass the assertion test'.
var schema = Joi.object().keys({
a: {
b: Joi.string(),
c: Joi.number()
},
d: {
e: Joi.any()
}
}).assert('d.e', Joi.ref('a.c'), 'equal to a.c');
Overrides the handling of unknown keys for the scope of the current object only (does not apply to children) where:
allow
- iffalse
, unknown keys are not allowed, otherwise unknown keys are ignored.
var schema = Joi.object({ a: Joi.any() }).unknown();
Requires the object to be an instance of a given constructor where:
constructor
- the constructor function that the object must be an instance of.name
- an alternate name to use in validation errors. This is useful when the constructor function does not have a name.
var schema = Joi.object().type(RegExp);
Sets the specified children to required.
children
- can be a single string value, an array of string values, or each child provided as an argument.
var schema = Joi.object().keys({ a: { b: Joi.number() }, c: { d: Joi.string() } });
var requiredSchema = schema.requiredKeys('', 'a.b', 'c', 'c.d');
Note that in this example ''
means the current object, a
is not required but b
is, as well as c
and d
.
Sets the specified children to optional.
children
- can be a single string value, an array of string values, or each child provided as an argument.
var schema = Joi.object().keys({ a: { b: Joi.number().required() }, c: { d: Joi.string().required() } });
var requiredSchema = schema.optionalKeys('a.b', 'c.d');
The behavior is exactly the same as requiredKeys
.
Generates a schema object that matches an ObjectId BSON type (as well as 24 character hex strings).
Supports the same methods of the any()
type.
var objectId = Joi.objectId();
objectId.validate('507f1f77bcf86cd799439011', function (err, value) { });
Generates a schema object that matches a string data type. Note that empty strings are not allowed by default and must be enabled with allow('')
.
Supports the same methods of the any()
type.
var schema = Joi.string().min(1).max(10);
schema.validate('12345', function (err, value) { });
Allows the value to match any whitelist of blacklist item in a case insensitive comparison.
var schema = Joi.string().valid('a').insensitive();
Specifies the minimum number string characters where:
limit
- the minimum number of string characters required.encoding
- is specified, the string length is calculated in bytes using the provided encoding.
var schema = Joi.string().min(2);
Specifies the maximum number of string characters where:
limit
- the maximum number of string characters allowed.encoding
- is specified, the string length is calculated in bytes using the provided encoding.
var schema = Joi.string().max(10);
Requires the number to be a credit card number (Using Lunh Algorithm).
var schema = Joi.string().creditCard();
Specifies the exact string length required where:
limit
- the required string length.encoding
- is specified, the string length is calculated in bytes using the provided encoding.
var schema = Joi.string().length(5);
Defines a regular expression rule where:
pattern
- a regular expression object the string value must match against.name
- optional name for patterns (useful with multiple patterns). Defaults to 'required'.
var schema = Joi.string().regex(/^[abc]+$/);
Requires the string value to only contain a-z, A-Z, and 0-9.
var schema = Joi.string().alphanum();
Requires the string value to only contain a-z, A-Z, 0-9, and underscore _.
var schema = Joi.string().token();
Requires the string value to be a valid email address.
options
- optional settings:errorLevel
- Numerical threshold at which an email address is considered invalid.tldWhitelist
- Specifies a list of acceptable TLDs.minDomainAtoms
- Number of atoms required for the domain. Be careful since some domains, such asio
, directly allow email.
var schema = Joi.string().email();
Requires the string value to be a valid GUID.
var schema = Joi.string().guid();
Requires the string value to be a valid hexadecimal string.
var schema = Joi.string().hex();
Requires the string value to be a valid hostname as per RFC1123.
var schema = Joi.string().hostname();
Requires the string value to be all lowercase. If the validation convert
option is on (enabled by default), the string
will be forced to lowercase.
var schema = Joi.string().lowercase();
Requires the string value to be all uppercase. If the validation convert
option is on (enabled by default), the string
will be forced to uppercase.
var schema = Joi.string().uppercase();
Requires the string value to contain no whitespace before or after. If the validation convert
option is on (enabled by
default), the string will be trimmed.
var schema = Joi.string().trim();
Generates a type that will match one of the provided alternative schemas via the try()
method. If no schemas are added, the type will not match any value except for undefined
.
Supports the same methods of the any()
type.
Alternatives can be expressed using the shorter []
notation.
var alt = Joi.alternatives().try(Joi.number(), Joi.string());
// Same as [Joi.number(), Joi.string()]
Adds an alternative schema type for attempting to match against the validated value where:
schema
- an array of alternative joi types. Also supports providing each type as a separate argument.
var alt = Joi.alternatives().try(Joi.number(), Joi.string());
alt.validate('a', function (err, value) { });
Adds a conditional alternative schema type based on another key (not the same as any.when()
) value where:
ref
- the key name or reference.options
- an object with:is
- the required condition joi type.then
- the alternative schema type to try if the condition is true. Required ifotherwise
is missing.otherwise
- the alternative schema type to try if the condition is false. Required ifthen
is missing.
var schema = {
a: Joi.alternatives().when('b', { is: 5, then: Joi.string(), otherwise: Joi.number() }),
b: Joi.any()
};
Note that when()
only adds additional alternatives to try and does not impact the overall type. Setting
a required()
rule on a single alternative will not apply to the overall key. For example,
this definition of a
:
var schema = {
a: Joi.alternatives().when('b', { is: true, then: Joi.required() }),
b: Joi.boolean()
};
Does not turn a
into a required key when b
is true
. Instead, it tells the validator to try and match the
value to anything that's not undefined
. However, since Joi.alternatives()
by itself allows undefined
, the rule
does not accomplish turning a
to a required value. This rule is the same as Joi.alternatives([Joi.required()])
when b
is true
which will allow any value including undefined
.
To accomplish the desired result above use:
var schema = {
a: Joi.when('b', { is: true, then: Joi.required() }),
b: Joi.boolean()
};
Generates a reference to the value of the named key. References are resolved at validation time and in order of dependency so that if one key validation depends on another, the dependent key is validated second after the reference is validated. References support the following arguments:
key
- the reference target. References cannot point up the object tree, only to sibling keys, but they can point to their siblings' children (e.g. 'a.b.c') using the.
separator. If akey
starts with$
is signifies a context reference which is looked up in thecontext
option object.options
- optional settings:separator
- overrides the default.
hierarchy separator.contextPrefix
- overrides the default$
context prefix signifier.
Note that references can only be used where explicitly supported such as in valid()
or invalid()
rules. If upwards
(parents) references are needed, use object.assert()
.
var schema = Joi.object().keys({
a: Joi.ref('b.c'),
b: {
c: Joi.any()
},
c: Joi.ref('$x')
});
Joi.validate({ a: 5, b: { c: 5 } }, schema, { context: { x: 5 } }, function (err, value) {});
See the API Reference.
Joi doesn't directly support browsers, but you could use joi-browser for an ES5 build of Joi that works in browsers, or as a source of inspiration for your own builds.