Add debug logs

qew.ts

@@ -1,3 +1,6 @@
+/**
+ * This returns a promise along with two functions to remotely ~detonate~ trigger either a resolution of rejection of the promise from elsewhere in the code. It's magic!
+ */
 function makeTriggerablePromise<T>(): [
   Promise<T>,
   (inp: T) => void,
@@ -13,19 +16,24 @@ function makeTriggerablePromise<T>(): [
   return [promToReturn, triggerResolveWith, triggerRejectWith];
 }
 
+export type Options = { debug?: boolean };
+
 export class Qew {
   private queue: (() => void)[] = [];
   private executing = 0;
+  private debug = false;
 
   /**
    *
    * @param maxConcurrent how many functions can be run simultaneously
    * @param delay how many ms to wait between when one function has resolved and
    * the next one is run
+   * @param options the only option currently supported is `debug`, which if enabled prints debugging logs
    */
   constructor(
     private maxConcurrent = 1,
-    private delay: number | (() => number) = 0
+    private delay: number | (() => number) = 0,
+    options?: Options
   ) {
     if (maxConcurrent < 1) {
       throw new Error("maxConcurrent has to be 1 or higher");
@@ -35,8 +43,26 @@ export class Qew {
         "`delay` parameter should be either a non-negative number or a function that returns one"
       );
     }
+
+    this.debug = options?.debug ?? this.debug;
+
+    this.debugLog(
+      `Debugging for Qew enabled! This qew has a maxConcurrent of ${maxConcurrent} and a ${
+        typeof delay === "number"
+          ? `delay of ${delay}ms`
+          : "custom delay generator function"
+      }`
+    );
+
+    this.tryMove = this.tryMove.bind(this);
+    this.push = this.push.bind(this);
+    this.pushProm = this.pushProm.bind(this);
+    this.debugLog = this.debugLog.bind(this);
   }
 
+  private debugLog = (...args: Parameters<typeof console.log>) =>
+    this.debug ? console.log(...args) : undefined;
+
   /**
    * Push another async function onto the queue
    * @param asyncFunc the async function to push onto this queue
@@ -56,14 +82,18 @@ export class Qew {
           const delay =
             typeof this.delay === "function" ? this.delay() : this.delay;
 
-          setTimeout(this.tryMove, delay);
+          this.debugLog(
+            `Function resolved! About to tryMove again after ${delay}ms. (At ${new Date()})`
+          );
+
+          setTimeout(() => this.tryMove("promise completion"), delay);
         })
         .catch(rejectProm);
     };
 
     this.queue.push(funcToRun);
 
-    this.tryMove();
+    this.tryMove("push");
 
     return prom;
   }
@@ -73,14 +103,27 @@ export class Qew {
    */
   public pushProm = this.push;
 
-  private tryMove() {
+  private tryMove(triggeredBy: "push" | "promise completion") {
+    this.debugLog(
+      `Trying to move because of: ${triggeredBy} (at unix time ${new Date()})`
+    );
+
     if (this.executing < this.maxConcurrent) {
       const first = this.queue.shift();
+      this.debugLog(
+        `Under execution limit! ${
+          first ? "Grabbed a function off the queue" : "Nothing on the queue"
+        }`
+      );
 
       if (first) {
         this.executing = this.executing + 1;
         first();
       }
+    } else {
+      this.debugLog(
+        `Currently at execution limit of ${this.maxConcurrent} so stopped move attempt`
+      );
     }
   }
 }