Interface: Joi

Properties

Property	Type	Description
cache	CacheConfiguration	-
override	symbol	A special value used with any.allow(), any.invalid(), and any.valid() as the first value to reset any previously set values.
ValidationError	(message: string, details: ValidationErrorItem[], original: any) => ValidationError	-
version	string	Current version of the joi package.

Methods

allow()

allow(...values: any[]): Schema;

Whitelists a value

Parameters

Parameter	Type
...values	any[]

Returns

Schema

---

alt()

Call Signature

alt<TSchema>(types: SchemaLike[]): AlternativesSchema<TSchema>;

Alias for alternatives

Type Parameters

Type Parameter	Default type
TSchema	any

Parameters

Parameter	Type
types	SchemaLike[]

Returns

AlternativesSchema<TSchema>

Call Signature

alt<TSchema>(...types: SchemaLike[]): AlternativesSchema<TSchema>;

Type Parameters

Type Parameter	Default type
TSchema	any

Parameters

Parameter	Type
...types	SchemaLike[]

Returns

AlternativesSchema<TSchema>

---

alternatives()

Call Signature

alternatives<TSchema>(types: SchemaLike[]): AlternativesSchema<TSchema>;

Generates a type that will match one of the provided alternative schemas

Type Parameters

Type Parameter	Default type
TSchema	any

Parameters

Parameter	Type
types	SchemaLike[]

Returns

AlternativesSchema<TSchema>

Call Signature

alternatives<TSchema>(...types: SchemaLike[]): AlternativesSchema<TSchema>;

Type Parameters

Type Parameter	Default type
TSchema	any

Parameters

Parameter	Type
...types	SchemaLike[]

Returns

AlternativesSchema<TSchema>

---

any()

any<TSchema>(): AnySchema<TSchema>;

Generates a schema object that matches any data type.

Type Parameters

Type Parameter	Default type
TSchema	any

Returns

AnySchema<TSchema>

---

array()

array<TSchema>(): ArraySchema<TSchema>;

Generates a schema object that matches an array data type.

Type Parameters

Type Parameter	Default type
TSchema	any[]

Returns

ArraySchema<TSchema>

---

assert()

Call Signature

assert(
   value: any,
   schema: Schema,
   options?: ValidationOptions): void;

Validates a value against a schema and throws if validation fails.

Parameters

Parameter	Type	Description
value	any	the value to validate.
schema	Schema	the schema object.
options?	ValidationOptions	-

Returns

void

Call Signature

assert(
   value: any,
   schema: Schema,
   message: string | Error,
   options?: ValidationOptions): void;

Parameters

Parameter	Type
value	any
schema	Schema
message	string | Error
options?	ValidationOptions

Returns

void

---

attempt()

Call Signature

attempt<TSchema>(
   value: any,
   schema: TSchema,
   options?: ValidationOptions): TSchema extends Schema<Value> ? Value : never;

Validates a value against a schema, returns valid object, and throws if validation fails.

Type Parameters

Type Parameter
TSchema extends Schema<any>

Parameters

Parameter	Type	Description
value	any	the value to validate.
schema	TSchema	the schema object.
options?	ValidationOptions	-

Returns

TSchema extends Schema<Value> ? Value : never

Call Signature

attempt<TSchema>(
   value: any,
   schema: TSchema,
   message: string | Error,
   options?: ValidationOptions): TSchema extends Schema<Value> ? Value : never;

Type Parameters

Type Parameter
TSchema extends Schema<any>

Parameters

Parameter	Type
value	any
schema	TSchema
message	string | Error
options?	ValidationOptions

Returns

TSchema extends Schema<Value> ? Value : never

---

binary()

binary<TSchema>(): BinarySchema<TSchema>;

Generates a schema object that matches a Buffer data type (as well as the strings which will be converted to Buffers).

Type Parameters

Type Parameter	Default type
TSchema	Buffer

Returns

BinarySchema<TSchema>

---

bool()

bool<TSchema>(): BooleanSchema<TSchema>;

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 boolean().

Type Parameters

Type Parameter	Default type
TSchema	boolean

Returns

BooleanSchema<TSchema>

---

boolean()

boolean<TSchema>(): BooleanSchema<TSchema>;

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().

Type Parameters

Type Parameter	Default type
TSchema	boolean

Returns

BooleanSchema<TSchema>

---

build()

build(...args: any[]): any;

Unsure, maybe alias for compile?

Parameters

Parameter	Type
...args	any[]

Returns

any

---

checkPreferences()

checkPreferences(prefs: ValidationOptions): void;

Checks if the provided preferences are valid.

Throws an exception if the prefs object is invalid.

The method is provided to perform inputs validation for the any.validate() and any.validateAsync() methods. Validation is not performed automatically for performance reasons. Instead, manually validate the preferences passed once and reuse.

Parameters

Parameter	Type
prefs	ValidationOptions

Returns

void

---

compile()

compile(schema: SchemaLike, options?: CompileOptions): Schema;

Converts literal schema definition to joi schema object (or returns the same back if already a joi schema object).

Parameters

Parameter	Type
schema	SchemaLike
options?	CompileOptions

Returns

Schema

---

custom()

custom(fn: CustomValidator, description?: string): Schema;

Creates a custom validation schema.

Parameters

Parameter	Type
fn	CustomValidator
description?	string

Returns

Schema

---

date()

date<TSchema>(): DateSchema<TSchema>;

Generates a schema object that matches a date type (as well as a JavaScript date string or number of milliseconds).

Type Parameters

Type Parameter	Default type
TSchema	Date

Returns

DateSchema<TSchema>

---

defaults()

defaults(fn: SchemaFunction): Root;

Creates a new Joi instance that will apply defaults onto newly created schemas through the use of the fn function that takes exactly one argument, the schema being created.

Parameters

Parameter	Type	Description
fn	SchemaFunction	The function must always return a schema, even if untransformed.

Returns

Root

---

disallow()

disallow(...values: any[]): Schema;

Parameters

Parameter	Type
...values	any[]

Returns

Schema

---

equal()

equal(...values: any[]): Schema;

Parameters

Parameter	Type
...values	any[]

Returns

Schema

---

exist()

exist(): Schema;

Alias of required.

Returns

Schema

---

expression()

expression(template: string, options?: ReferenceOptions): any;

Generates a dynamic expression using a template string.

Parameters

Parameter	Type
template	string
options?	ReferenceOptions

Returns

any

---

extend()

extend(...extensions: (Extension | ExtensionFactory)[]): any;

Creates a new Joi instance customized with the extension(s) you provide included.

Parameters

Parameter	Type
...extensions	(Extension | ExtensionFactory)[]

Returns

any

---

forbidden()

forbidden(): Schema;

Marks a key as forbidden which will not allow any value except undefined. Used to explicitly forbid keys.

Returns

Schema

---

func()

func<TSchema>(): FunctionSchema<TSchema>;

Generates a schema object that matches a function type.

Type Parameters

Type Parameter	Default type
TSchema	Function

Returns

FunctionSchema<TSchema>

---

function()

function<TSchema>(): FunctionSchema<TSchema>;

Generates a schema object that matches a function type.

Type Parameters

Type Parameter	Default type
TSchema	Function

Returns

FunctionSchema<TSchema>

---

in()

in(ref: string, options?: ReferenceOptions): Reference;

Creates a reference that when resolved, is used as an array of values to match against the rule.

Parameters

Parameter	Type
ref	string
options?	ReferenceOptions

Returns

Reference

---

invalid()

invalid(...values: any[]): Schema;

Blacklists a value

Parameters

Parameter	Type
...values	any[]

Returns

Schema

---

isError()

isError(error: any): error is ValidationError;

Checks whether or not the provided argument is an instance of ValidationError

Parameters

Parameter	Type
error	any

Returns

error is ValidationError

---

isExpression()

isExpression(expression: any): boolean;

Checks whether or not the provided argument is an expression.

Parameters

Parameter	Type
expression	any

Returns

boolean

---

isRef()

isRef(ref: any): ref is Reference;

Checks whether or not the provided argument is a reference. It's especially useful if you want to post-process error messages.

Parameters

Parameter	Type
ref	any

Returns

ref is Reference

---

isSchema()

isSchema(schema: any, options?: CompileOptions): schema is AnySchema<any>;

Checks whether or not the provided argument is a joi schema.

Parameters

Parameter	Type
schema	any
options?	CompileOptions

Returns

schema is AnySchema<any>

---

link()

link<TSchema>(ref?: string): LinkSchema<TSchema>;

Links to another schema node and reuses it for validation, typically for creative recursive schemas.

Type Parameters

Type Parameter	Default type
TSchema	any

Parameters

Parameter	Type	Description
ref?	string	the reference to the linked schema node. Cannot reference itself or its children as well as other links. Links can be expressed in relative terms like value references (Joi.link('...')), in absolute terms from the schema run-time root (Joi.link('/a')), or using schema ids implicitly using object keys or explicitly using any.id() (Joi.link('#a.b.c')).

Returns

LinkSchema<TSchema>

---

not()

not(...values: any[]): Schema;

Parameters

Parameter	Type
...values	any[]

Returns

Schema

---

number()

number<TSchema>(): NumberSchema<TSchema>;

Generates a schema object that matches a number data type (as well as strings that can be converted to numbers).

Type Parameters

Type Parameter	Default type
TSchema	number

Returns

NumberSchema<TSchema>

---

object()

object<TSchema, isStrict, T>(schema?: SchemaMap<T, isStrict>): ObjectSchema<TSchema>;

Generates a schema object that matches an object data type (as well as JSON strings that have been parsed into objects).

Type Parameters

Type Parameter	Default type
TSchema	any
isStrict	false
T	TSchema

Parameters

Parameter	Type
schema?	SchemaMap<T, isStrict>

Returns

ObjectSchema<TSchema>

---

optional()

optional(): Schema;

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.

Returns

Schema

---

options()

options(...args: any[]): any;

Unsure, maybe alias for preferences?

Parameters

Parameter	Type
...args	any[]

Returns

any

---

preferences()

preferences(options: ValidationOptions): Schema;

Overrides the global validate() options for the current key and any sub-key.

Parameters

Parameter	Type
options	ValidationOptions

Returns

Schema

---

prefs()

prefs(options: ValidationOptions): Schema;

Overrides the global validate() options for the current key and any sub-key.

Parameters

Parameter	Type
options	ValidationOptions

Returns

Schema

---

ref()

ref(key: string, options?: ReferenceOptions): Reference;

Generates a reference to the value of the named key.

Parameters

Parameter	Type
key	string
options?	ReferenceOptions

Returns

Reference

---

required()

required(): Schema;

Marks a key as required which will not allow undefined as value. All keys are optional by default.

Returns

Schema

---

string()

string<TSchema>(): StringSchema<TSchema>;

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('').

Type Parameters

Type Parameter	Default type
TSchema	string

Returns

StringSchema<TSchema>

---

symbol()

symbol<TSchema>(): SymbolSchema<TSchema>;

Generates a schema object that matches any symbol.

Type Parameters

Type Parameter	Default type
TSchema	Symbol

Returns

SymbolSchema<TSchema>

---

trace()

trace(...args: any[]): any;

Unsure, maybe leaked from @hapi/lab/coverage/initialize

Parameters

Parameter	Type
...args	any[]

Returns

any

---

types()

types(): {
  alternatives: AlternativesSchema;
  any: AnySchema;
  array: ArraySchema;
  binary: BinarySchema;
  boolean: BooleanSchema;
  date: DateSchema;
  function: FunctionSchema;
  link: LinkSchema;
  number: NumberSchema;
  object: ObjectSchema;
  string: StringSchema;
  symbol: SymbolSchema;
};

Returns an object where each key is a plain joi schema type. Useful for creating type shortcuts using deconstruction. Note that the types are already formed and do not need to be called as functions (e.g. string, not string()).

Returns

{
  alternatives: AlternativesSchema;
  any: AnySchema;
  array: ArraySchema;
  binary: BinarySchema;
  boolean: BooleanSchema;
  date: DateSchema;
  function: FunctionSchema;
  link: LinkSchema;
  number: NumberSchema;
  object: ObjectSchema;
  string: StringSchema;
  symbol: SymbolSchema;
}

Name	Type
alternatives	AlternativesSchema
any	AnySchema
array	ArraySchema
binary	BinarySchema
boolean	BooleanSchema
date	DateSchema
function	FunctionSchema
link	LinkSchema
number	NumberSchema
object	ObjectSchema
string	StringSchema
symbol	SymbolSchema

---

untrace()

untrace(...args: any[]): any;

Parameters

Parameter	Type
...args	any[]

Returns

any

---

valid()

valid(...values: any[]): Schema;

Adds the provided values into the allowed whitelist and marks them as the only valid values allowed.

Parameters

Parameter	Type
...values	any[]

Returns

Schema

---

when()

Call Signature

when(ref: string | Reference, options: WhenOptions | WhenOptions[]): AlternativesSchema;

Converts the type into an alternatives type where the conditions are merged into the type definition where:

Parameters

Parameter	Type
ref	string | Reference
options	WhenOptions | WhenOptions[]

Returns

AlternativesSchema

Call Signature

when(ref: Schema, options: WhenSchemaOptions): AlternativesSchema;

Parameters

Parameter	Type
ref	Schema
options	WhenSchemaOptions

Returns

AlternativesSchema

---

x()

x(template: string, options?: ReferenceOptions): any;

Generates a dynamic expression using a template string.

Parameters

Parameter	Type
template	string
options?	ReferenceOptions

Returns

any