From: Ardis Lu <ardisglu@gmail.com>
Date: Fri, 4 Jul 2025 03:45:55 +0000 (-0700)
Subject: Simplify and harden tick indicator
X-Git-Tag: v0.1.2~5
X-Git-Url: https://git.ardis.lu/?a=commitdiff_plain;h=57396cd5682b88aebcadad7ab5e45f9db4a3df5b;p=csvio

Simplify and harden tick indicator

Relying on physical timing is flaky (e.g., it will fail if executing on a slow machine).  Sending a simple `tick` increment into the task queue is more reliable.
---

diff --git a/examples/data/ex3_2-out.csv b/examples/data/ex3_2-out.csv
index de20589..334d7d3 100644
--- a/examples/data/ex3_2-out.csv
+++ b/examples/data/ex3_2-out.csv
@@ -1,9 +1,9 @@
 tick number,concurrent group
-1,a
-1,a
-1,a
-1,a
-1,a
-2,b
-2,b
-2,b
+0,a
+0,a
+0,a
+0,a
+0,a
+5,b
+5,b
+5,b
diff --git a/examples/ex3_2.js b/examples/ex3_2.js
index bf341b6..7f83dc6 100644
--- a/examples/ex3_2.js
+++ b/examples/ex3_2.js
@@ -7,19 +7,12 @@
 // takes very long, all row processing is blocked on the 1 transformation even if all others in the group have already
 // resolved.
 
-import { setTimeout } from 'node:timers/promises';
 import { CSVReader, CSVTransformer, CSVWriter } from '../src/index.js';
 
-// Returns how many 100ms increments have elapsed since this program began
-const start = performance.now();
-function tick() {
-  const ms = performance.now() - start;
-  return Math.floor(ms / 100);
-}
-
+let tick = 0;
 async function concurrent(row) {
-  await setTimeout(100); // Simulate some slow task, e.g. a network request
-  return [tick(), ...row];
+  setTimeout(() => tick++, 0); // Tick will only be incremented after the concurrent group is done
+  return [tick, ...row];
 }
 
 await new CSVReader(new URL('./data/ex3_2-in.csv', import.meta.url))