eyepatch

A library of notification based objects

Installation

npm install eyepatch --save

Why?

Sometimes you just want to know when something happens without the need of checking it yourself. You just want to be notified when the change happens.

Who?

Just me myself and I, in my free time

Features

• Events - Simple or parametrized.
• ConditionalEvent - Simple or parametrized.
• GlobalEvent - To broadcast events globally
• ObservableCollection - notifies you when something changes.
• ObservableDictionary - Works with keys as an object and not only strings and numbers. Notifies on changes. Works simply adding non enumerable property as the key id. This doesn't affect the JSON.stringify method nor the for in loop.

Languages

The library is written in TypeScript but you can use in both in TypeScript and JavaScript

Usage examples in TypeScript

Using parametrized event:

var event = new EventT<number>();

event.on((_num: number) => console.log('The number ' + _num + ' was raised'));

event.raise(15);

Using conditional event

var conditionalEvent = new ConditionalEventT<number>();

conditionalEvent.on(
  (_num) => console.log('The number ' + _num + ' is positive'),
  (_num) => _num > 0
  );

conditionalEvent.raise(-1); // Will not be logged
conditionalEvent.raise(12); // Will be logged

Using global event

const globalEvent1 = new GlobalEvent();

globalEvent1.on('some event name', (_num: number) => console.log('The number ' + _num + ' was raised'));

// In some other place
const globalEvent2 = new GlobalEvent();
globalEvent2.raise('some event name', 123); // Will log: "The number 123 was raised"

Raising safely in case one of the registrations throws an error

var event = new Event();

event.on(() => throw 'some error');
event.on(() => console.log('I still want to log'));

event.raiseSafe();

Using ObservableCollection

var collection = new ObservableCollection<number>();

var items:number[] = collection.items;

collection.itemsChanged.on(
  (_args: IItemsChangedEventArgs<number>) => {
    console.log('Added items: ' + _args.added);
    console.log('Removed items: ' + _args.removed);
  });

collection.add(2);
collection.addRange([1,2,3,4,5,6,7,8,9]);

collection.removeMatching(2);
collection.removeMatchingRange([5,6]);
collection.removeAtIndex(0);
collection.removeAtIndices([0,1]);

var size: number = collection.size;

var has7: boolean = collection.contains(7);

collection.clear();

Using ObservableDictionary

var dictionary = new ObservableDictionary<Obejct, Object>();

dictionary.itemsChanged.on(
  _args => {
    console.log('Added key value pairs: ' + _args.added);
    console.log('Removed key value pairs: ' + _args.removed);
  });

var key = { someProp: 1 };
var value = {};
dictionary.add(key, value);

// Be aware: containsKey will work only on keys instances that are inside the dictionary
var containsKey: boolean = dictionary.containsKey(key);
var containsValue: boolean = dictionary.containsValue(value);

// Be aware: getValueByKey will work only on keys instances that are inside the dictionary
var valueByKey: Object = dictionary.getValueByKey(key);

var size: number = dictionary.size;

var keys: Object[] = dictionary.keys;
var values: Object[] = dictionary.values;
var keysAndValues: IKeyValue<Object, Object>[] = dictionary.keysAndValues;

// Be aware: removing will work only on keys instances that are inside the dictionary
dictionary.remove(key);

// If you don't have the instance you can search it:
var foundKey = dictionary.findKey(_ => _.someProp === 1);
dictionary.containsKey(foundKey);
dictionary.getValueByKey(foundKey);
dictionary.remove(foundKey);

dictionary.clear();

Whats next?

Have fun and feel free to use, comment, request, and contribute. I'll keep adding stuff from time to time