yinso / typelet

Typelet - an extensible type framework.

Install

npm install typelet

Usage

var Type = require('typelet');

Type checking:

Type.baseEnv.get('integer').isa(1); // ==> true
Type.baseEnv.get('integer').isa(1.5); // ==> false
Type.baseEnv.get('float').isa(1.5); // ==> true

// compound types.
var intArrayType = Type.baseEnv.get('array')(Type.baseEnv.get('integer'))
intArrayType.isa([1, 2, 3, 4, 5]); // ==> true
var objFooType = Type.baseEnv.get('object')({ foo: Type.baseEnv.get('integer'), bar: Type.baseEnv.get('string') });
objFooType.isa({foo: 1, bar: 'a string'}); // ==> true
objFooType.isa({foo: 1, baz: 2}); // ==> false

Type checking via assert:

Type.baseEnv.get('integer').assert(1); // OK
Type.baseEnv.get('integer').assert(1.5); // throws
intArrayType.assert([1, 'not an int']); // throws
objFooType.assert({foo: 1, bar: 'a string'}); // OK
objFooType.assert({foo: 1, bar: 'a string', baz: 2}); // OK - ObjectType is okay with additional attributes.
objFooType.assert({foo: 1, bar: 2}); // throws

Type conversion:

var val = Type.baseEnv.get('integer').convert('1'); // string -> int
var val = Type.baseEnv.get('integer').convert('not an int'); // throws

JSON Schema support (limited at this time):

var schema = Type.Schema({
  definitions: {
    foo: { type: 'integer' },
bar: {
  type: 'object',
  properties: {
    foo: { $ref: '#/definitions/foo' },
    baz: { type: 'number' }
  }
},
baz: {
  type: 'object'
  properties: {
    xyz: { $ref: '#/definitions/bar' },
    abc: {
      type: 'array',
      items: { type: 'boolean' }
    }
  }
},
abc: {
  type: 'integer',
  default: 50
}
  }
});
schema.get('foo').isa(1) // true
schema.get('bar').isa({ foo: 1, bar: 2.5 }) // true
schema.get('baz').isa({ xyz: { foo: 1, bar: 2.5 }, abc: [ true, false, true ] }) // true
schema.get('abc').isa(10) // true
schema.get('abc').convert() // ==> 50, default val works.

Built-In Types

Built-in types currently follows JavaScript built-in types.

• Scalar Types
  • unit (Type.baseEnv.get('unit')) - maps to undefined in JavaScript.
  • null (Type.baseEnv.get('null')) - maps to null in JavaScript.
  • boolean (Type.baseEnv.get('boolean')) maps to true and false in JavaScript.
  • integer (Type.baseEnv.get('integer'))
  • float (Type.baseEnv.get('float')) - NaN is not considered a number in this type system.
  • string (Type.baseEnv.get('string'))
  • date (Type.baseEnv.get('date'))
• Compound Types
  • array (Type.baseEnv.get('array')(<type>))
  • object (Type.baseEnv.get('object')({ key1: <type1>, key2: <type2>, ...}))
  • disjoint union (Type.baseEnv.get('oneOf')(<type1>, <type2>, ...))
  • procedure (Type.baseEnv.get('procedure')([<argType1>, ...], <returnType>))