core-decorators

core-decorators.js

Library of ES7 decorators inspired by languages that come with built-ins like @​override, @​deprecate, etc, similar to pre-defined Annotations in Java.

The idea is these decorators would be used to ensure code sanity, but would be removed in production builds via a Babel plugin.

@readonly

Marks a property or method as not being writable.

import { readonly } from 'core-decorators';

class Woman {
  @readonly
  gender = 'female';
}

var lady = new Woman();
lady.gender = 'male';
// Cannot assign to read only property 'gender' of [object Object]

@override

Checks that the marked method indeed overrides a function with the same signature somewhere on the prototype chain.

Works with methods and getters/setters. Will ensure name, parameter count, as well as descriptor type (accessor/data). Provides a suggestion if it finds a method with a similar signature, including slight misspellings.

import { override } from 'core-decorators';

class Parent {
  kickDog(first, second) {}
}

class Child extends Parent {
  @override
  kickDog() {}
  // SyntaxError: Child#kickDog() does not properly override Parent#kickDog(first, second)
}

// or

class Child extends Parent {
  @override
  kickDogs() {}
  // SyntaxError: No descriptor matching Child#kickDogs() was found on the prototype chain.
  //
  //   Did you mean "kickDog"?
}

@deprecate (alias: @deprecated)

Calls console.warn() with a deprecation message. Provide a custom message to override the default one. You can also provide an options hash with a url, for further reading.

import { deprecate } from 'core-decorators';

class Person {
  @deprecate
  kickDog() {}

  @deprecate('We stopped animal abuse')
  kickDogHard() {}
 
  @deprecate('We stopped animal abuse', { url: 'http://humanesociety.org/issues/abuse_neglect/' })
  kickDogHarder() {}
}

let person = new Person();

person.kickDog();
// DEPRECATION Person#kickDog: This function will be removed in future versions.

person.kickDogHard();
// DEPRECATION Person#kickDogHard: We stopped animal abuse

person.kickDogHarder();
// DEPRECATION Person#kickDogHarder: We stopped animal abuse
//
//     See http://humanesociety.org/issues/abuse_neglect/ for more details.
//

@suppressWarnings

Suppresses any JavaScript console.warn() call while the decorated function is called. (i.e. on the stack)

Will not suppress warnings triggered in any async code within.

import { suppressWarnings } from 'core-decorators';

class Person {
  @deprecated
  kickDog() {}
  
  @suppressWarnings
  kickDogWithoutWarning() {
    this.kickDog();
  }
}

let person = new Person();

person.kickDogWithoutWarning();
// no warning is logged

@memoize

Initial implementation included, likely slow. WIP.

Disclaimer

Please don't kick dogs. It's not nice.