FIx: Implement the missing logics.

Author: jamallaqdiem

implement-shell-tools/.gitignore

@@ -0,0 +1 @@
+.venv

implement-shell-tools/cat/cat.js

@@ -10,6 +10,16 @@ const showNonBlankNumbers = argv.includes("-b");
 
 //filter the - from the array argv as it's a flag.
 const filePaths = argv.filter((arg) => !arg.startsWith("-"));
+
+const flagsUsed = argv.filter((arg) => arg.startsWith("-"));
+const supportedFlags = ["-n", "-b"];
+for (const flag of flagsUsed) {
+  if (!supportedFlags.includes(flag)) {
+    console.error(`Invalid option try 'node cat.js --help' for more info.`);
+    process.exit(1);
+  }
+}
+
 let counterLines = 1;
 
 for (const path of filePaths) {
@@ -20,21 +30,19 @@ for (const path of filePaths) {
     const splitLines = content.split("\n");
 
     splitLines.forEach((line) => {
-      if (showNumbers) {
-        console.log(`${counterLines++}  ${line}`);
-      } else if (showNonBlankNumbers) {
-        // increment and show numbers only if the line is not empty.
+      let prefix = "";
+
+      if (showNonBlankNumbers) {
         if (line.trim() !== "") {
-          console.log(`${counterLines++}  ${line}`);
-        } else {
-          // print empty lines
-          console.log(line);
+          prefix = `${counterLines++}  `;
         }
-      } else {
-        console.log(line);
+      } else if (showNumbers) {
+        prefix = `${counterLines++}  `;
       }
+      console.log(`${prefix}${line}`);
     });
   } catch (error) {
-    console.log(`Could not read: ${path}`);
+    console.error(`Could not read: ${path}`);
+    process.exit(1);
   }
 }

implement-shell-tools/ls/ls.js

@@ -8,6 +8,10 @@ const argv = process.argv.slice(2);
 const filePaths = argv.filter((arg) => !arg.startsWith("-"));
 const showHiddenFiles = argv.includes("-a");
 
+if (filePaths.length > 1) {
+  console.error("Error: This version only supports one directory path a time.");
+  process.exit(1);
+}
 // if no folder provide we use the current one
 const target = filePaths[0] || ".";
 // read the file.

implement-shell-tools/wc/wc.js

@@ -3,16 +3,22 @@ import fs from "node:fs";
 
 const argv = process.argv.slice(2);
 
-const showWords = argv.includes("-w");
-const showLines = argv.includes("-l");
-const showBytes = argv.includes("-c");
-const showCharacters = argv.includes("-m");
+let showWords = argv.includes("-w");
+let showLines = argv.includes("-l");
+let showBytes = argv.includes("-c");
+let showCharacters = argv.includes("-m");
 
 //  filter flags, and getting the string of filename
 const filePaths = argv.filter((arg) => !arg.startsWith("-"));
-
-const noFlags = !showLines && !showCharacters && !showWords && !showCharacters;
-if (!filePaths) {
+// if no flags enable all.
+if (!showLines && !showCharacters && !showWords && !showBytes) {
+  showLines = true;
+  showCharacters = true;
+  showWords = true;
+  showBytes = true;
+}
+// fix bug .length ===0 will be true if nothing provided, instead !filePath will return empty array which result true.
+if (filePaths.length === 0) {
   console.error("PLease provide a file path");
   process.exit(1);
 }
@@ -31,10 +37,10 @@ filePaths.forEach((filePath) => {
 
   let output = "";
 
-  if (showLines || noFlags) output += `${lines} `;
-  if (showWords || noFlags) output += `${words} `;
-  if (showBytes || noFlags) output += `${bytes} `;
-  if (showCharacters || noFlags) output += `${characters} `;
+  if (showLines) output += `${lines} `;
+  if (showWords) output += `${words} `;
+  if (showBytes) output += `${bytes} `;
+  if (showCharacters) output += `${characters} `;
 
   console.log(`${output} ${filePath}`);
 });