add 4.3 solution

Author: kasymbayaman

04-callback-patterns/4.2-list-files-recursively.js

@@ -17,12 +17,11 @@ function listNestedFiles(dirPath, cb) {
     } else {
       for (const file of files) {
         result.runningOps++;
-        readDirectory(path.join(dirPath, file), cb);
+        listNestedFiles(path.join(dirPath, file), cb);
       }
     }
 
     result.runningOps--;
-
     process.nextTick(() => {
       if (!result.runningOps) return cb(null, result.fileList);
     });

04-callback-patterns/4.3-recursive-find.js

@@ -0,0 +1,40 @@
+import fs from "fs";
+import path from "path";
+
+const result = {
+  runningOps: 1,
+  fileList: [],
+};
+
+function recursiveFind(dirPath, searchText, cb) {
+  fs.readdir(dirPath, {}, (err, files) => {
+    if (err) {
+      if (err.code !== "ENOTDIR") return cb(err);
+      searchInFile(dirPath, searchText, cb);
+    } else {
+      for (const file of files) {
+        result.runningOps++;
+        recursiveFind(path.join(dirPath, file), searchText, cb);
+      }
+
+      finishOp(cb);
+    }
+  });
+}
+
+function searchInFile(dirPath, searchText, cb) {
+  fs.readFile(dirPath, "utf8", (err, data) => {
+    if (err) return cb(err);
+
+    if (data.includes(searchText)) result.fileList.push(dirPath);
+    finishOp(cb);
+  });
+}
+
+function finishOp(cb) {
+  result.runningOps--;
+
+  process.nextTick(() => {
+    if (!result.runningOps) return cb(null, result.fileList);
+  });
+}

04-callback-patterns/DIR/SUBDIR/subdirFile0.txt

@@ -0,0 +1 @@
+batman snyder cut

04-callback-patterns/DIR/SUBDIR/subdirFile1.txt

@@ -0,0 +1 @@
+batman cut

04-callback-patterns/DIR/SUBDIR/subdirFile2.txt

@@ -0,0 +1 @@
+snyder

04-callback-patterns/DIR/SUBDIR/subdirFile3.txt

@@ -0,0 +1 @@
+c

04-callback-patterns/DIR/SUBDIR/subdirFile4.txt

@@ -0,0 +1 @@
+batman

04-callback-patterns/DIR/file0.txt

@@ -0,0 +1 @@
+batman snyder cut

04-callback-patterns/DIR/file1.txt

@@ -0,0 +1 @@
+snyder cut

04-callback-patterns/DIR/file2.txt

@@ -0,0 +1 @@
+batman

04-callback-patterns/DIR/file3.txt

@@ -0,0 +1 @@
+cut

04-callback-patterns/DIR/file4.txt

@@ -0,0 +1 @@
+snyder