Refactor task runner implementation to TypeScript

.gitignore

@@ -2,3 +2,5 @@
 node_modules/
 .idea/
 test.txt
+package-lock.json
+dist/

contributors.txt

@@ -1 +1,2 @@
 Odigie Oseme U.
+Ikpefua Harrison V.

lib/Task.ts

@@ -0,0 +1,18 @@
+/**
+ * Created by osemeodigie on 30/05/2017.
+ */
+import { TaskRunner } from "./TaskRunner"
+
+// Example Task
+interface DoneCallback {
+    (taskRunner: TaskRunner, time?: number): void;
+}
+
+export default function Task($this: TaskRunner, done_callback: DoneCallback): void {
+    var time: number = Math.random() * 8000;
+    setTimeout(function() {
+        console.log('task complete', time);
+        done_callback($this, time);
+    }, time);
+    console.log('task started', time);
+}

lib/TaskRunner.ts

@@ -0,0 +1,69 @@
+/**
+ * Created by osemeodigie on 30/05/2017.
+ */
+
+export class TaskRunner {
+    max_task_limit: number;
+    _currently_running_task: number;
+    _tasks: Array<(runner: TaskRunner, done: (runner: TaskRunner, time?: number) => void) => void | any>;
+    _is_task_running: boolean;
+    currentTask?: (runner: TaskRunner, done: (runner: TaskRunner, time?: number) => void) => void | any;
+
+    constructor(throttle_limit?: number) {
+        this.max_task_limit = (throttle_limit === undefined) ? 2 : throttle_limit;
+        this._currently_running_task = 0;
+        this._tasks = [];
+        this._is_task_running = false;
+
+        // Binded the doneTask method to the current instance so this method doesn't lose context when used as a callback
+        // this.doneTask = this.doneTask.bind(this);
+    }
+
+    private runNextTask(): boolean {
+        // Check if there are any other pending tasks
+        if (this._tasks.length === 0) {
+            console.log("No task found currently on stack");
+            return false;
+        }
+
+        if (this._currently_running_task >= this.max_task_limit) {
+            return false;
+        }
+
+        this.currentTask = this._tasks.shift();
+        if (this.currentTask) {
+            this._currently_running_task += 1; // Taken a task to run
+            console.log("\n Scheduling task");
+            this._is_task_running = true;
+            this.currentTask(this, this.doneTask); // Execute the task
+        }
+        return true;
+    }
+
+    private doneTask($this: TaskRunner, time?: number): void {
+
+        // decrement my current task counter...
+        $this._currently_running_task -= 1;
+        $this._is_task_running = false;
+
+        if ($this._tasks.length > 0) {
+            $this._is_task_running = true;
+            $this.runNextTask();
+        }
+
+        if ($this._is_task_running && $this._tasks.length === 0) {
+            console.log("Finished scheduling all tasks to run...");
+        }
+
+        if (!$this._is_task_running && $this._tasks.length === 0) {
+            console.log("Finished running all tasks!");
+        }
+    }
+
+    public addTask(task: (runner: TaskRunner, done: (runner: TaskRunner, time?: number) => void) => void): void {
+        this._tasks.push(task);
+        if (this._tasks.length > 0) {
+            this.runNextTask();
+        }
+    }
+}

package.json

@@ -8,7 +8,8 @@
     "url": "http://osemeodigie.com"
   },
   "scripts": {
-    "start": "node task_runner_test.js",
+    "test": "jest",
+    "start": "tsc && node dist/task_runner_test.js",
     "lint": "jshint **/*.js",
     "postmerge": "npm install",
     "pretest": "npm run lint"
@@ -20,6 +21,11 @@
   "devDependencies": {
     "jshint": "latest",
     "should": "^11.0.0",
-    "supertest": "^2.0.0"
+    "supertest": "^2.0.0",
+    "@types/jest": "^29.5.14",
+    "eslint": "^9.25.1",
+    "jest": "^29.7.0",
+    "ts-jest": "^29.3.2",
+    "typescript": "^5.8.3"
   }
 }

task_runner_test.js → task_runner_test.ts

@@ -2,8 +2,8 @@
  * Created by osemeodigie on 30/05/2017.
  */
 
-var task    = require("./lib/Task")
-var TaskRunner    = require("./lib/TaskRunner")
+import task from "./lib/Task"
+import { TaskRunner } from "./lib/TaskRunner"
 
 console.log("Started the task runner test file...")
 
@@ -21,16 +21,16 @@ taskRunner.addTask(task) // task 7
 taskRunner.addTask(task) // task 8
 taskRunner.addTask(task) // task 9
 taskRunner.addTask(task) // task 10
-taskRunner.addTask(task) // task 11
-taskRunner.addTask(task) // task 12
-taskRunner.addTask(task) // task 13
-taskRunner.addTask(task) // task 14
-taskRunner.addTask(task) // task 15
-taskRunner.addTask(task) // task 16
-taskRunner.addTask(task) // task 17
-taskRunner.addTask(task) // task 18
-taskRunner.addTask(task) // task 19
-taskRunner.addTask(task) // task 20
+// taskRunner.addTask(task) // task 11
+// taskRunner.addTask(task) // task 12
+// taskRunner.addTask(task) // task 13
+// taskRunner.addTask(task) // task 14
+// taskRunner.addTask(task) // task 15
+// taskRunner.addTask(task) // task 16
+// taskRunner.addTask(task) // task 17
+// taskRunner.addTask(task) // task 18
+// taskRunner.addTask(task) // task 19
+// taskRunner.addTask(task) // task 20
 
 
 // task started 123.23232

tsconfig.json

@@ -0,0 +1,12 @@
+{
+    "compilerOptions": {
+    "module": "commonjs",
+    "esModuleInterop": true,
+    "target": "es6",
+    "moduleResolution": "node",
+    "sourceMap": true,
+    "outDir": "dist"
+    },
+    "lib": ["es2015"],
+    "include": ["lib/**/*", "task_runner_test.ts"],
+}