README

An assert library for AtScript based on tcomb type combinators.

Setup

npm install tcomb-ats

Add the following keys to your traceur options:

{
  "types": true,
  "typeAssertions": true,
  "typeAssertionModule": "path/to/tcomb-ats",
  "annotations": true // if you also want annotations
}

Set "typeAssertions": false in production.

Demo

git clone https://github.com/gcanti/tcomb-ats.git
cd tcomb-ats
npm install
gulp

Open ./example/index.html in a browser.

Syntax

Primitives

var t = require('tcomb-ats');
var Str = t.Str;

// strings
var s: Str = 'a'; // ok
var s: Str = null; // throws (tcomb's primitives are not nullable)
var s: Str = 1; // throws

// numbers
var Num = t.Num;
var n: Num = 1; // ok

// booleans
var Bool = t.Bool;
var b: Bool = true; // ok

// you can use other irreducible types provided by tcomb
// or define your own, see tcomb documentation

Nullable types

Use the maybe<T> combinator:

var s: maybe<Str> = 'a'; // ok
var s: maybe<Str> = null; // ok

Functions

function sum(a: Num, b: Num): Num {
  return a + b;
}

sum(1, 2); // ok
sum(1, 'a'); // throws

Lists

Use the list<T> combinator:

var list = t.list;

var a: list<Str> = ['a']; // ok
var b: list<Str> = [1]; // throws

// you can also use the `Array<T>` syntax
var c: Array<Str> = ['a'];

Classes

class Person {
  constructor(name: Str, surname: Str) {
    this.name = name;
    this.surname = surname;
  }
}

var p1: Person = new Person('Giulio', 'Canti'); // ok
var p2: Person = new Person('Giulio'); // throws

Tuples

Use the tuple combinator:

var tuple = t.tuple;

var t: tuple<Str, Num> = [1, 'a']; // ok
var t: tuple<Str, Num> = [1, 2]; // throws

Dicts

Use the dict combinator:

var dict = t.dict;

var d: dict<Str, Num> = {a: 1}; // ok
var d: dict<Str, Num> = {a: 'b'}; // throws

Enums

Use the enums combinator:

var Align = t.enums.of('left center right');

var e: Align = 'left'; // ok
var e: Align = 'justify'; // throws

Subtypes

Use the subtype combinator:

var Positive = t.subtype(Num, function (n) {
  return n >= 0;
});

var n: Positive = 1; // ok
var n: Positive = -1; // throws
var n: Positive = 'a'; // throws

Unions

Use the union combinator:

var StrOrNum = t.union([Str, Num]);

var u: StrOrNum = 'a'; // ok
var u: StrOrNum = 1; // ok
var u: StrOrNum = true; // throws

tcomb's structs

var Person = t.struct({
  name: t.Str,
  surname: t.Str
});

var p: Person = new Person({
  name: 'Giulio',
  surname: 'Canti'}
); // ok
var p: Person = 1; // throws

License

The MIT License (MIT)

Usage no npm install needed!