Rewrite lstat in 3 different styles

tshemsedinov · tshemsedinov · commit 5508faf4c30d · 2023-07-17T08:21:30.000+03:00
diff --git a/JavaScript/4-lstat-bad.js b/JavaScript/4-lstat-bad.js
@@ -0,0 +1,26 @@
+'use strict';
+
+const fs = require('node:fs');
+
+const files = ['1-readFileSync.js', 'n-untitled.js', '3-async.js'];
+
+const stats = new Array(files.length);
+
+let rest = files.length;
+
+const printResult = () => {
+  console.dir({ stats });
+};
+
+files.forEach((file, i) => {
+  console.dir({ file, i });
+  fs.lstat(file, (err, stat) => {
+    if (err) {
+      console.log(`File ${file} not found`);
+    } else {
+      stats[i] = stat;
+    }
+    if (--rest) return;
+    printResult();
+  });
+});
diff --git a/JavaScript/4-lstat-callback.js b/JavaScript/4-lstat-callback.js
@@ -0,0 +1,18 @@
+'use strict';
+
+const fs = require('node:fs');
+
+const stats = (files, done) => {
+  const result = {};
+  for (const file of files) {
+    const res = {};
+    fs.lstat(file, (err, stat) => {
+      result[file] = { err, stat };
+      const count = Object.keys(result).length;
+      if (count === files.length) done(result);
+    });
+  }
+};
+
+const files = ['1-readFileSync.js', 'n-untitled.js', '3-async.js'];
+stats(files, console.dir);
diff --git a/JavaScript/4-lstat-collector.js b/JavaScript/4-lstat-collector.js
@@ -0,0 +1,32 @@
+'use strict';
+
+const fs = require('node:fs');
+
+class KeyCollector {
+  constructor(keys, onDone) {
+    this.expected = new Set(keys);
+    this.onDone = onDone;
+    this.finished = false;
+    this.data = new Map();
+  }
+
+  collect(key, value) {
+    if (this.finished) return this;
+    this.data.set(key, value);
+    if (this.expected.size === this.data.size) {
+      this.finished = true;
+      this.onDone(this.data);
+    }
+    return this;
+  }
+}
+
+const files = ['1-readFileSync.js', 'n-untitled.js', '3-async.js'];
+
+const stats = new KeyCollector(files, console.dir);
+
+for (const fileName of files) {
+  fs.lstat(fileName, (err, stat) => {
+    stats.collect(fileName, err || stat);
+  });
+}
diff --git a/JavaScript/4-lstat-promise.js b/JavaScript/4-lstat-promise.js
