Add promisify adapter example

tshemsedinov · tshemsedinov · commit 579960f3f805 · 2024-07-15T03:51:00.000+03:00
diff --git a/JavaScript/8-promisify.js b/JavaScript/8-promisify.js
@@ -0,0 +1,31 @@
+'use strict';
+
+const promisify = (fn) => (...args) => {
+  const promise = new Promise((resolve, reject) => {
+    const callback = (err, data) => {
+      if (err) reject(err);
+      else resolve(data);
+    };
+    fn(...args, callback);
+  });
+  return promise;
+};
+
+// Usage
+
+const fs = require('node:fs');
+const read = promisify(fs.readFile);
+
+const main = async () => {
+  const fileName = '8-promisify.js';
+  const data = await read(fileName, 'utf8');
+  console.log(`File "${fileName}" size: ${data.length}`);
+  try {
+    const data = await read('unknown.file', 'utf8');
+    console.log(`File size: ${data.length}`);
+  } catch (error) {
+    console.error(error.message);
+  }
+};
+
+main();
