Add support for combined notifications

src/backend/base.ts

@@ -4,7 +4,7 @@ import { Task } from "../types/task";
 export abstract class Backend<C extends BackendSettings> {
   public abstract readonly name: string;
   protected abstract requiredFields: readonly (keyof C)[];
-  protected abstract notify(config: C, task: Task): void;
+  protected abstract notify(config: C, task: Task): void;  
 
   #validate(config: Partial<C>): C {
     for (const field of this.requiredFields) {
@@ -16,13 +16,27 @@ export abstract class Backend<C extends BackendSettings> {
     return config as C;
   }
 
-  public remind(config: Config, task: Task) {
+  public async remind(config: Config, tasks: Task[]): Promise<void> {
     const cfg = config?.backend?.[this.name] as Partial<C> | undefined;
 
     if (cfg?.enable !== true) {
-      return
+      return;
     }
 
-    this.notify(this.#validate(cfg), task);
+    if (tasks.length === 0) {
+      return;
+    }
+
+    if (tasks.length === 1) {
+      return await this.notify(this.#validate(cfg), tasks[0]);
+    }
+
+    return await this.notifyCombined(this.#validate(cfg), tasks);
+  }
+
+  protected async notifyCombined(config: C, tasks: Task[]) {
+    for (const task of tasks) {
+      this.notify(config, task);
+    }
   }
 }

src/backend/index.ts

@@ -28,15 +28,7 @@ async function run(config: Config, db: TaskDatabase, tasks?: Task[]) {
     return;
   }
 
-  for (const task of tasks) {
-    console.info(`Dispatching a notification: [${task.label}]`)
-    for (const backend of backends) {      
-      backend.remind(config, task);
-      await snooze(1500);
-    }
+  for (const backend of backends) {
+    await backend.remind(config, tasks);
   }
-}
-
-function snooze(ms: number) {
-  return new Promise(resolve => setTimeout(resolve, ms));
 }

src/backend/ntfy.ts

@@ -8,7 +8,8 @@ import { jsMapper } from "../util/code";
 type Config = {
   url: string;
   token: string;
-  mapper?: string;
+  map?: string;
+  combineMap?: string;
   topic?: string;
 } & BackendSettings;
 
@@ -25,28 +26,74 @@ export class NtfySH extends Backend<Config> {
 
   protected requiredFields = ['url', 'token'] as const;
   
-  protected notify(config: Config, task: Task): void {    
-    const token = enhancedStringConfig(config.token);
-    const mapper = config.mapper
-      ? jsMapper<object, NtfyDTO>(config.mapper, { mapPriority })
+  protected notify(config: Config, task: Task): void {        
+    const context = { 
+      mapPriority,
+      template: defaultMapper
+    };
+    
+    const mapper = config.map
+      ? jsMapper<object, NtfyDTO>(config.map, context)
       : defaultMapper;
 
     const dto = mapper(task);
 
+    this.#doNotify(config, dto);
+  }
+
+  protected async notifyCombined(config: Config, tasks: Task[]): Promise<void> {
+    const chunks = chunkArray(tasks, 4);
+
+    const context = {
+      mapPriority,
+      template: defaultCombineMapper
+    };
+
+    for (const chunk of chunks) {
+      const mapper = config.combineMap
+        ? jsMapper<object, NtfyDTO>(config.combineMap, context)
+        : defaultCombineMapper;
+
+      const dto = mapper(chunk);
+
+      await this.#doNotify(config, dto);
+
+      await snooze(2500);
+    }
+  }
+
+  async #doNotify(config: Config, dto: NtfyDTO): Promise<Response> {
+    const token = enhancedStringConfig(config.token);
+
     const headers: Record<string, string> = {
       Authorization: `Bearer ${token}`
     };    
 
     buildHeaders(dto, headers);
 
-    fetch(`https://${config.url}/${config.topic || 'obsidian'}`, {
+    return fetch(`https://${config.url}/${config.topic || 'obsidian'}`, {
       method: 'POST', 
       body: dto.text ?? "",
       headers
-    })    
+    })
   }
 }
 
+function snooze(ms: number) {
+  return new Promise(resolve => setTimeout(resolve, ms));
+}
+
+function chunkArray<T>(array: T[], size: number): T[][] {
+  const chunks = [];
+
+  while (array.length) {
+    chunks.push(array.slice(0, size));
+    array = array.slice(size);
+  }
+
+  return chunks;
+}
+
 function buildHeaders(dto: NtfyDTO, headers: Record<string, string>) {
   if (dto.title) {
     headers.Title = dto.title;
@@ -74,6 +121,23 @@ function defaultMapper(task: Task): NtfyDTO {
   }
 }
 
+function defaultCombineMapper(tasks: Task[], bullet = "-"): NtfyDTO {
+  const text = tasks
+    .toSorted((a, b) => b.priority - a.priority)
+    .map(t => `${bullet} ${t.label}`)
+    .join("\n");
+    
+  const priority = mapPriority(Math.max(...tasks.map(t => t.priority)));
+  const tags = tasks.flatMap(t => t.tags);
+
+  return {
+    title: `Obsidian Task Reminder (${tasks.length})`,    
+    text,
+    priority,
+    tags
+  }
+}
+
 function mapPriority(priority?: TaskPriority): string {
   if (!priority) {
     return 'default';

src/util/code.ts

@@ -1,4 +1,4 @@
 export function jsMapper<I, O>(code: string, context: Record<string, unknown>): (task: I) => O {
-  const filter = new Function('$', ...Object.keys(context), `return ${code};`);
+  const filter = new Function('$', ...Object.keys(context), code);
   return (task: I) => filter(task, ...Object.values(context));
 }

tsconfig.json

@@ -1,6 +1,6 @@
 {
   "compilerOptions": {
-    "target": "ES2020",
+    "target": "ES2023",
     "module": "commonjs",
     "outDir": "./dist",
     "rootDir": "./src",