Implement wc command to count lines, words and characters

Author: ike-agu

implement-shell-tools/wc/wc.js

@@ -0,0 +1,80 @@
+import { program } from "commander";
+import { promises as fs } from "node:fs";
+import process from "node:process";
+
+program
+  .name("wc command")
+  .description("Implement wc command to count words and lines")
+  .option("-l,", "show number of lines only")
+  .option("-w,", "show number of words only")
+  .option("-c,", "show number of characters only")
+  .argument("[path...]", "The file path to process");
+
+program.parse(process.argv);
+
+const opts = program.opts();
+let paths = program.args;
+
+if (paths.length === 0) {
+  console.error("wc: no file specified");
+  process.exit(1);
+}
+
+let totals = { lines: 0, words: 0, chars: 0 };
+
+for (const filePath of paths) {
+  let content;
+  try {
+    content = await fs.readFile(filePath, "utf8");
+  } catch (err) {
+    console.error(`wc: cannot read file "${filePath}": ${err.message}`);
+    continue; // move on to next path
+  }
+
+  const lineCount = content.split("n").length;
+
+  const wordCount = content.split(/\s+/).filter(Boolean).length;
+
+  const charCount = content.length;
+
+  totals.lines += lineCount;
+  totals.words += wordCount;
+  totals.chars += charCount;
+
+  // Decide what to print depending on flags
+  if (!opts.l && !opts.w && !opts.c) {
+    console.log(`${lineCount} ${wordCount} ${charCount} ${filePath}`);
+    continue;
+  }
+
+  if (opts.l) {
+    console.log(`${lineCount} ${filePath}`);
+  }
+
+  if (opts.w) {
+    console.log(`${wordCount} ${filePath}`);
+  }
+
+  if (opts.c) {
+    console.log(`${charCount} ${filePath}`);
+  }
+}
+
+//Print totals if there are multiple files
+if (paths.length > 1) {
+  if (!opts.l && !opts.w && !opts.c) {
+    console.log(`${totals.lines} ${totals.words} ${totals.chars} total`);
+  }
+
+  if (opts.l) {
+    console.log(`${totals.lines} total`);
+  }
+
+  if (opts.w) {
+    console.log(`${totals.words} total`);
+  }
+
+  if (opts.c) {
+    console.log(`${totals.chars} total`);
+  }
+}