feat: implement in memory store

1. the store works as a temporary store for connection data such as chats, messages & contacts
2. the store is primarily meant to illustrate the usage of the event emitter as a way to construct the state of the connection. This will likely be very inefficient to perform well at scale
3. the store is meant to be a quick way to have some visibility of data while testing
4. the store works for both legacy & MD connections

src/Store/make-ordered-dictionary.ts

@@ -0,0 +1,86 @@
+function makeOrderedDictionary<T>(idGetter: (item: T) => string) {
+	const array: T[] = []
+	const dict: { [_: string]: T } = { }
+
+	const get = (id: string) => dict[id]
+
+	const update = (item: T) => {
+		const id = idGetter(item)
+		const idx = array.findIndex(i => idGetter(i) === id)
+		if(idx >= 0) {
+			array[idx] = item
+			dict[id] = item
+		}
+
+		return false
+	}
+
+	const upsert = (item: T, mode: 'append' | 'prepend') => {
+		const id = idGetter(item)
+		if(get(id)) {
+			update(item)
+		} else {
+			if(mode === 'append') {
+				array.push(item)
+			} else {
+				array.splice(0, 0, item)
+			}
+
+			dict[id] = item
+		}
+	}
+	
+	const remove = (item: T) => {
+		const id = idGetter(item)
+		const idx = array.findIndex(i => idGetter(i) === id)
+		if(idx >= 0) {
+			array.splice(idx, 1)
+			delete dict[id]
+			return true
+		}
+
+		return false
+	}
+
+	return {
+		array,
+		get,
+		upsert,
+		update,
+		remove,
+		updateAssign: (id: string, update: Partial<T>) => {
+			const item = get(id)
+			if(item) {
+				Object.assign(item, update)
+				delete dict[id]
+				dict[idGetter(item)] = item
+				return true
+			}
+
+			return false
+		},
+		clear: () => {
+			array.splice(0, array.length)
+			Object.keys(dict).forEach(key => {
+				delete dict[key] 
+			})
+		},
+		filter: (contain: (item: T) => boolean) => {
+			let i = 0
+			while(i < array.length) {
+				if(!contain(array[i])) {
+					delete dict[idGetter(array[i])]
+					array.splice(i, 1)
+				} else {
+					i += 1
+				}
+			}
+		},
+		toJSON: () => array,
+		fromJSON: (newItems: T[]) => {
+			array.splice(0, array.length, ...newItems)
+		}
+	}
+}
+
+export default makeOrderedDictionary