README
typonator
A small library to work with types in Javascript.
- Typonator creates data types, not classes or module-like structures.
- Typonator creates plain Javascript objects
- Typonator has no dependencies!
- Typonator weighs only ~1kb minified!
- Typonator lets you create custom value types
- Works with libraries like lodash or underscore for value type checking
Guide
Installation
npm install typonator
Creating types
Typonator lets you create type factories. You can use the built in value types of typonator:
var t = require('typonator')
var user = t.create({
name: t.string
age: t.number
})
Default values
By chaining a type checker with .default(value) you can specify a default. If the property is not defined or undefined, it will use the default one (it will not type check the default value).
var point = create({
x: t.number.default(0)
y: t.number.default(0)
})
var treeTop = point({ y: 20 }) // => { x: 0, y: 20 }
Custom value type checkers
You can also create custom type checkers, give a name and a predicate that returns true or false. This allows you to create your own specialized type checkers or use libraries like lodash or underscore. Custom types can also have default values.
var user = t.create({
age: t.custom('int', _.isInteger), // using lodash
gender: t.custom('gender', isGender)
})
function isGender (value) {
return value === 'm' || value === 'f'
}
Nesting types
Types are nestable using t.type(nestedType).
var car = t.create({
price: t.number
})
var owner = t.create({
name: t.string,
car: t.type(car)
})
var pete = owner({
name: 'Pete',
car: {
price: '30000'
}
})
/* pete = {
name: 'Pete',
car: {
price: '30000'
}
} */
Using types
Use types as follows:
var john = user({
name: 'John Doe',
age: 32
})
/* john = {
name: 'John Doe',
age: 32
} */
Types throw an error when the wrong, or not all values are provided
// Trows an error
var john = user({
name: 'John Doe',
age: 'thirty-two'
})
// Also trows an error
var john = user({
age: 32
})
var john = user({
name: 'John Doe',
age: 32
})
Types ignore and filter out non-specified properties
var john = user({
name: 'John Doe',
age: 32,
gender: 'male'
})
/* john = {
name: 'John Doe',
age: 32
} */