API.md

API

Assert library

A type is represented by an object with 2 properties:

• name: string
• validate: function

The validate function has the following signature:

validate(x: any, ctx: ?Array<any>, fast: ?boolean): ?Array<Failure>

where

Failure = {
  actual: any;
  expected: Type;
  path: Array<string | number>;
}

transform(source: string, options: ?object): string

Options:

• namespace: string (default f)
• sourceMap: boolean (default false)
• target: string (one of ["es3"])

f.define(name: string, is: (x: any) => boolean): Type

Defines a new basic type.

f.check(value: T, type: Type): T

• by default instanceof is used to check the type
• if type owns a static is(x: any), it will be used to check the type
• if value is not of type type, f.fail will be called with a meaningful error message

f.list(type: Type, name: ?string): Type

Returns a type representing the list Array<type>.

f.tuple(types: Array<Type>, name: ?string): Type

Returns a type representing the tuple [...types].

f.shape(props: {[key:string]: Type}): Type

Returns a type representing the object {p1: T1, p2: T2, ... p3: T3}.

f.dict(domain: Type, codomain: Type, name: ?string): Type

Returns a type representing the dictionary type {[key: domain]: codomain}.

f.maybe(type: Type, name: ?string): Type

Returns a type representing the nullable type ?type.

f.union(types: Array<Type>, name: ?string): Type

Returns a type representing the union T1 | T2 | ... | Tn.