Refactor output handling in cat, ls, and wc commands for improved formatting

Author: mervereis

implement-shell-tools/cat/cat.js

@@ -25,10 +25,14 @@ let lineNumber = 1;
 for (const file of files) {
   try {
     const contents = fs.readFileSync(file, "utf8");
-    const lines = contents.split("\n");
+    const hasTrailingNewline = contents.endsWith("\n");
+    const lines = hasTrailingNewline
+      ? contents.slice(0, -1).split("\n")
+      : contents.split("\n");
 
     lines.forEach((line, index) => {
-      const output = index < lines.length - 1 ? line + "\n" : line;
+      const output =
+        index < lines.length - 1 || hasTrailingNewline ? line + "\n" : line;
 
       if (numberNonBlank) {
         if (line.trim() === "") {

implement-shell-tools/ls/ls.js

@@ -43,7 +43,7 @@ for (let i = 0; i < paths.length; i++) {
       }
 
       if (!onePerLine) {
-        console.log();
+        process.stdout.write("\n");
       }
     }
   } catch (error) {

implement-shell-tools/wc/wc.js

@@ -31,6 +31,20 @@ let totalWords = 0;
 let totalBytes = 0;
 let filesCounted = 0;
 
+function formatResult(lines, words, bytes, fileName) {
+  let result = "";
+  if (countLines) {
+    result += String(lines).padStart(8);
+  }
+  if (countWords) {
+    result += String(words).padStart(8);
+  }
+  if (countBytes) {
+    result += String(bytes).padStart(8);
+  }
+  return result + " " + fileName;
+}
+
 function countFile(fileName) {
   try {
     const content = fs.readFileSync(fileName, "utf8");
@@ -44,18 +58,7 @@ function countFile(fileName) {
     totalWords += words;
     totalBytes += bytes;
     filesCounted++;
-    let result = "";
-    if (countLines) {
-      result += lines + " ";
-    }
-    if (countWords) {
-      result += words + " ";
-    }
-    if (countBytes) {
-      result += bytes + " ";
-    }
-    result += fileName;
-    console.log(result);
+    console.log(formatResult(lines, words, bytes, fileName));
   } catch (error) {
     console.log("Cannot read file: " + fileName);
   }
@@ -66,17 +69,5 @@ for (let file of files) {
 }
 
 if (filesCounted > 1) {
-  let result = "";
-  if (countLines) {
-    result += totalLines + " ";
-  }
-  if (countWords) {
-    result += totalWords + " ";
-  }
-  if (countBytes) {
-    result += totalBytes + " ";
-  }
-  result += "total";
-
-  console.log(result);
+  console.log(formatResult(totalLines, totalWords, totalBytes, "total"));
 }