Add -b flag using commander

Author: zohrehKazemianpour

implement-shell-tools/cat/cat.js

@@ -1,6 +1,5 @@
-import {program} from "commander";
-import {promises as fs} from "node:fs"
-
+import { program } from "commander";
+import { promises as fs } from "node:fs";
 
 //here we Configure the program: what flags and arguments it accepts
 // .option("short, long", "description")
@@ -10,35 +9,46 @@ program
   .name("cat")
   .description("concatenate and print files")
   .option("-n, --number", "Number all output lines")
+  .option("-b, --numberNonBlank", "Number non-blank output lines")
   .argument("<path>", "The file path to process");
 
 // here Parse command line arguments (reads process.argv and interprets it)
 program.parse();
 
-
 // Get the parsed values
 const path = program.args[0]; // The filename user provided
-const hasNumberFlag = program.opts().number;    // True if user used -n flag
+const hasNumberFlag = program.opts().number; // True if user used -n flag
+const hasBFlag = program.opts().numberNonBlank;
 
 //read the file
-const content = await fs.readFile(path, "utf-8")
+const content = await fs.readFile(path, "utf-8");
 
 // Output with or without line numbers
 if (hasNumberFlag) {
+  
   // Add line numbers to each line
   const lines = content.split("\n"); // Split into array of lines
   const numberedLines = lines.map((line, index) => {
-    const numberOfLine = index + 1; // Convert 0-based index to 1-based line number
-    return `${numberOfLine} ${line}`; // Format: "     1  Hello"
+    const lineNumber = index + 1; // Convert 0-based index to 1-based line number
+    return `${lineNumber} ${line}`; // Format: "     1  Hello"
   });
   console.log(numberedLines.join("\n")); // Join back with newlines
+} else if (hasBFlag) {
+  console.log("Using -b flag!");
+  let lineNumber = 0;
+  const lines = content.split("\n");
+  console.log("Total lines:", lines.length);
+  const numberedLines = lines.map((line) => {
+     console.log(`Line: "${line}", isEmpty: ${line.trim() === ""}`);  
+    if (line.trim() === "") {
+      return line;
+    } else {
+      lineNumber = lineNumber + 1;
+      return ` ${lineNumber} ${line}`
+    }
+  });
+console.log(numberedLines.join("\n"));
 } else {
   // Just print the file as-is
   console.log(content);
 }
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