https://github.com/mattphillips/trait-contract

Utility to build a Trait (Interface) for a given Type and supply an implementation which is validated against the Trait contract
https://github.com/mattphillips/trait-contract

contract interface trait

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Utility to build a Trait (Interface) for a given Type and supply an implementation which is validated against the Trait contract

• Host: GitHub
• URL: https://github.com/mattphillips/trait-contract
• Owner: mattphillips
• License: mit
• Created: 2016-11-30T22:52:22.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2020-04-24T23:17:45.000Z (about 5 years ago)
• Last Synced: 2025-01-29T09:44:59.073Z (5 months ago)
• Topics: contract, interface, trait
• Language: JavaScript
• Homepage:
• Size: 14.6 KB
• Stars: 1
• Watchers: 3
• Forks: 0
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Trait Contract

[![Build Status](https://travis-ci.org/mattphillips/trait-contract.svg?branch=master)](https://travis-ci.org/mattphillips/trait-contract)

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Utility to build a Trait (Interface) for a given Type. The Trait's contract is used to validate against the implementation, throwing an `Error` if the implementation is missing a property of the Trait.

If an implementation conforms to it's Trait then the given functions are validated for the number of arguments they are invoked with, throwing an `Error` if called with too few or too many arguments.

## Example

``` js

const Database = Trait({

  create: ['x'],

  read: [],

  update: ['id', 'x'],

  delete: ['id']

});

const InMemoryDatabase = {

  create: (x) => { ... },

  read: () => { ... },

  update: (id, x) => { ... },

  delete: (id) => { ... }

};

const PersistentDatabase = {

  create: (x) => { ... },

  read: () => { ... },

  update: (id, x) => { ... }

};

const app = (dbImpl) => {

  const db = Database.impl(dbImpl);

  // Calling create function with one argument conforms to Database Trait's

  // contract and runs the implementation of create function with 'Hello, world!'.

  db.create('Hello, world!');

  // Calling create function with two arguments does not conform to the Database

  // Trait's contract so an Error is thrown because create function expects to

  // receive one argument.

  db.create('Hello,', 'world!');

}

// InMemoryDatabase conforms to Database Trait's contract used by app so no Error is thrown.

app(InMemoryDatabase);

// PersistentDatabase does not conform to Database Trait's contract used by app

// so an Error is thrown because the delete function is missing from the implementation.

app(PersistentDatabase);

```