London | 26-SDC-MAR | Jamal Laqdiem | Sprint 3 | Implement Shell Tools

implement-shell-tools/.gitignore

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+.venv

implement-shell-tools/cat/cat.js

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+import process from "node:process";
+import { promises as fs } from "node:fs";
+
+// THis will give an array without the path to node and to the file.
+const argv = process.argv.slice(2);
+
+//Get line numbers.
+const showNumbers = argv.includes("-n");
+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) {
+  try {
+    const content = await fs.readFile(path, "utf-8");
+
+    //split the text at the new line character.
+    const splitLines = content.split("\n");
+
+    splitLines.forEach((line) => {
+      let prefix = "";
+
+      if (showNonBlankNumbers) {
+        if (line.trim() !== "") {
+          prefix = `${counterLines++}  `;
+        }
+      } else if (showNumbers) {
+        prefix = `${counterLines++}  `;
+      }
+      console.log(`${prefix}${line}`);
+    });
+  } catch (error) {
+    console.error(`Could not read: ${path}`);
+    process.exit(1);
+  }
+}

implement-shell-tools/ls/ls.js

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+import fs from "node:fs";
+import process from "node:process";
+
+// This will give an array without the path to node and to the file.
+const argv = process.argv.slice(2);
+
+// filter the flag to find the target folder.
+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.
+const files = fs.readdirSync(target);
+
+// save the result into the variable.
+let filteredFIles = files;
+if (!showHiddenFiles) {
+  filteredFIles = files.filter((file) => !file.startsWith("."));
+} else {
+  // we use spread operator to merge the paths.
+  filteredFIles = [".", "..", ...files];
+}
+
+// Print using -1 .
+filteredFIles.forEach((file) => {
+  console.log(file);
+});

implement-shell-tools/wc/wc.js

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+import process, { exit } from "node:process";
+import fs from "node:fs";
+
+const argv = process.argv.slice(2);
+
+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("-"));
+// 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);
+}
+// loop trough the array to get each file path.
+filePaths.forEach((filePath) => {
+  const content = fs.readFileSync(filePath, "utf-8");
+
+  const lines = content.split("\n").length - 1;
+  const words = content
+    .trim()
+    .split(/\s+/)
+    .filter((word) => word != "").length;
+  // here I used Buffer.byteLength even if characters and bytes can be the same number .length, however sometimes an emoji or special characters can be heavier 2b or 4b
+  const bytes = Buffer.byteLength(content);
+  const characters = content.length;
+
+  let output = "";
+
+  if (showLines) output += `${lines} `;
+  if (showWords) output += `${words} `;
+  if (showBytes) output += `${bytes} `;
+  if (showCharacters) output += `${characters} `;
+
+  console.log(`${output} ${filePath}`);
+});