feat: getting started example of worker_threads

Author: chyingp

examples/2022.03.24-worker-threads/getting-started/index.js

@@ -0,0 +1,16 @@
+const stringify = require('./json-util');
+
+stringify({"uid": "10001"});
+stringify({"uid": "10002"});
+
+/*
+    输出日志如下，当 worker 通过 postMessage 给主线程发消息，1、父线程受到消息，并进入父线程的回调；2、父线程回调结束，子线程继续执行（postMessage后的逻辑）
+    [main thread] before processing, process.pid = 61000, thread id = 0, uid = 10001
+    [main thread] before processing, process.pid = 61000, thread id = 0, uid = 10002
+            [worker thread] start processing, process id = 61000, thread id = 1, uid = 10001
+    [main thread] message from worker[threadId = 1], process.pid = 61000, thread id = 0, uid = 10001
+            [worker thread] start processing, process id = 61000, thread id = 2, uid = 10002
+    [main thread] message from worker[threadId = 2], process.pid = 61000, thread id = 0, uid = 10002
+            [worker thread] finishing processing, process id = 61000, thread id = 1, uid = 10001
+            [worker thread] finishing processing, process id = 61000, thread id = 2, uid = 10002    
+*/

examples/2022.03.24-worker-threads/getting-started/json-util.js

@@ -0,0 +1,35 @@
+const {
+    Worker, isMainThread, parentPort, workerData, threadId
+  } = require('worker_threads');
+  
+  if (isMainThread) {
+    module.exports = function stringify(script) {
+      console.log(`[main thread] before processing, process.pid = ${process.pid}, thread id = ${threadId}, uid = ${script.uid}`);
+      return new Promise((resolve, reject) => {
+        const worker = new Worker(__filename, {
+          workerData: script
+        });
+        worker.on('message', (result) => {
+          console.log(`[main thread] message from worker[threadId = ${result.threadId}], process.pid = ${process.pid}, thread id = ${threadId}, uid = ${script.uid}`);
+          resolve(result)
+        });
+        worker.on('error', reject);
+        worker.on('exit', (code) => {
+          if (code !== 0)
+            reject(new Error(`Worker stopped with exit code ${code}`));
+        });
+      });
+    };
+  } else {
+    const threadId = require('worker_threads').threadId;
+    console.log(`\t[worker thread] start processing, process id = ${process.pid}, thread id = ${threadId}, uid = ${workerData.uid}`);
+    
+    function parse(jsonObj) {
+      return JSON.stringify(jsonObj);
+    }
+    
+    const script = workerData;
+    parentPort.postMessage({ jsonStr: parse(script), threadId: threadId } );
+    
+    console.log(`\t[worker thread] finishing processing, process id = ${process.pid}, thread id = ${threadId}, uid = ${workerData.uid}`);
+  }