Add more stuff to client

packages/client/src/clientData.ts

@@ -0,0 +1,93 @@
+import {Subscriber} from 'svelte/store'
+import {call} from '@welshman/lib'
+
+export class ClientData<T> {
+  selfSubscribers: Subscriber<ClientData<T>>[] = []
+  clearSubscribers: Subscriber<ClientData<T>>[] = []
+  itemSubscribers: Subscriber<T>[] = []
+  data = new Map<string, T>()
+
+  // Svelte store-like methods
+
+  private notify = () => {
+    for (const subscriber of this.selfSubscribers) {
+      subscriber(this)
+    }
+  }
+
+  subscribe = (subscriber: Subscriber<ClientData<T>>) => {
+    subscriber(this)
+    this.selfSubscribers.push(subscriber)
+
+    return () => {
+      this.selfSubscribers.splice(this.selfSubscribers.indexOf(subscriber), 1)
+    }
+  }
+
+  derived = (key: string) => {
+    return readable(this.get(key), set => {
+      const subscribers = [
+        this.onClear(() => set(undefined)),
+        this.onItem(set)
+      ]
+
+      return () => subscribers.forEach(call)
+    })
+  }
+
+  // EventEmitter-like methods
+
+  private emitClear = () => {
+    for (const subscriber of this.clearSubscribers) {
+      subscriber(this)
+    }
+
+    this.notify()
+  }
+
+  onClear = (subscriber: Subscriber<T>) => {
+    this.clearSubscribers.push(subscriber)
+
+    return () => {
+      this.clearSubscribers.splice(this.clearSubscribers.indexOf(subscriber), 1)
+    }
+  }
+
+  private emitItem = (item: T) => {
+    for (const subscriber of this.itemSubscribers) {
+      subscriber(item)
+    }
+
+    this.notify()
+  }
+
+  onItem = (subscriber: Subscriber<T>) => {
+    this.itemSubscribers.push(subscriber)
+
+    return () => {
+      this.itemSubscribers.splice(this.itemSubscribers.indexOf(subscriber), 1)
+    }
+  }
+
+  // Map-like methods
+
+  clear = () => {
+    this.data.clear()
+    this.emitClear()
+  }
+
+  delete = (key: string) => {
+    this.data.delete(key)
+    this.emitItem(key, undefined)
+  }
+
+  set = (key: string, value: T) => {
+    this.data.set(key, value)
+    this.emitItem(key, value)
+  }
+
+  get = (key: string) => this.data.get(key)
+  values = () => this.data.values()
+  items = () => this.data.items()
+  keys = () => this.data.keys()
+}