feat(js): improve @nx/js:node executor to be more resilient to many f…

…ile change events

docs/generated/packages/js/executors/node.json

@@ -59,6 +59,11 @@
         "type": "boolean",
         "description": "Enable re-building when files change.",
         "default": true
+      },
+      "debounce": {
+        "type": "number",
+        "description": "Delay in milliseconds to wait before restarting. Useful to batch multiple file changes events together. Set to zero (0) to disable.",
+        "default": 500
       }
     },
     "additionalProperties": false,

packages/js/package.json

@@ -50,7 +50,6 @@
     "js-tokens": "^4.0.0",
     "minimatch": "3.0.5",
     "source-map-support": "0.5.19",
-    "tree-kill": "1.2.2",
     "tslib": "^2.3.0",
     "@nx/devkit": "file:../devkit",
     "@nx/workspace": "file:../workspace"

packages/js/src/executors/node/lib/kill-tree.ts

@@ -0,0 +1,129 @@
+// Adapted from https://raw.githubusercontent.com/pkrumins/node-tree-kill/deee138/index.js
+import { spawn, exec, ExecException } from 'child_process';
+
+export async function killTree(pid: number, signal: NodeJS.Signals) {
+  const tree = {};
+  const pidsToProcess = {};
+  tree[pid] = [];
+  pidsToProcess[pid] = 1;
+
+  return new Promise<void>((resolve, reject) => {
+    const callback = (error: ExecException | null) => {
+      if (error) {
+        reject(error);
+      } else {
+        resolve();
+      }
+    };
+
+    switch (process.platform) {
+      case 'win32':
+        exec('taskkill /pid ' + pid + ' /T /F', callback);
+        break;
+      case 'darwin':
+        buildProcessTree(
+          pid,
+          tree,
+          pidsToProcess,
+          function (parentPid) {
+            return spawn('pgrep', ['-P', parentPid]);
+          },
+          function () {
+            killAll(tree, signal, callback);
+          }
+        );
+        break;
+      default: // Linux
+        buildProcessTree(
+          pid,
+          tree,
+          pidsToProcess,
+          function (parentPid) {
+            return spawn('ps', [
+              '-o',
+              'pid',
+              '--no-headers',
+              '--ppid',
+              parentPid,
+            ]);
+          },
+          function () {
+            killAll(tree, signal, callback);
+          }
+        );
+        break;
+    }
+  });
+}
+
+function killAll(tree, signal, callback) {
+  const killed = {};
+  try {
+    Object.keys(tree).forEach(function (pid) {
+      tree[pid].forEach(function (pidpid) {
+        if (!killed[pidpid]) {
+          killPid(pidpid, signal);
+          killed[pidpid] = 1;
+        }
+      });
+      if (!killed[pid]) {
+        killPid(pid, signal);
+        killed[pid] = 1;
+      }
+    });
+  } catch (err) {
+    if (callback) {
+      return callback(err);
+    } else {
+      throw err;
+    }
+  }
+  if (callback) {
+    return callback();
+  }
+}
+
+function killPid(pid, signal) {
+  try {
+    process.kill(parseInt(pid, 10), signal);
+  } catch (err) {
+    if (err.code !== 'ESRCH') throw err;
+  }
+}
+
+function buildProcessTree(
+  parentPid,
+  tree,
+  pidsToProcess,
+  spawnChildProcessesList,
+  cb
+) {
+  const ps = spawnChildProcessesList(parentPid);
+  let allData = '';
+  ps.stdout.on('data', (data) => {
+    data = data.toString('ascii');
+    allData += data;
+  });
+
+  const onClose = function (code) {
+    delete pidsToProcess[parentPid];
+
+    if (code != 0) {
+      // no more parent processes
+      if (Object.keys(pidsToProcess).length == 0) {
+        cb();
+      }
+      return;
+    }
+
+    allData.match(/\d+/g).forEach((_pid) => {
+      const pid = parseInt(_pid, 10);
+      tree[parentPid].push(pid);
+      tree[pid] = [];
+      pidsToProcess[pid] = 1;
+      buildProcessTree(pid, tree, pidsToProcess, spawnChildProcessesList, cb);
+    });
+  };
+
+  ps.on('close', onClose);
+}