01 Implement shell tools (cat, ls, wc) in JS with mode

Author: Nataliia74

implement-shell-tools/cat/cat.js

@@ -0,0 +1,33 @@
+import process from "node:process";
+import { promises as fs } from "node:fs";
+
+const arrArgv = process.argv.slice(2);
+
+const numberLines = arrArgv.includes("-n");
+const numberNonemptyLines = arrArgv.includes("-b");
+
+const nonFlagArrArgv = arrArgv.filter((arr) => !arr.startsWith("-"));
+
+let number = 1;
+
+for (let file of nonFlagArrArgv) {
+  const content = await fs.readFile(file, "utf-8");
+
+  const linedText = content.split("\n");
+
+  const numbered = linedText.map((line) => {
+    if (numberNonemptyLines) {
+      if (line.trim() === "") {
+        return line;
+      } else {
+        return `${String(number++).padStart(3)}  ${line}`;
+      }
+    }
+    if (numberLines) {
+      return `${String(number++).padStart(3)}  ${line}`;
+    }
+
+    return line;
+  });
+  console.log(numbered.join("\n"));
+}

implement-shell-tools/ls/ls.js

@@ -0,0 +1,56 @@
+import process from "node:process";
+import { promises as fs } from "node:fs";
+import path from "node:path";
+
+const arrArgv = process.argv.slice(2);
+
+const longFormat = arrArgv.includes("-l");
+const showHidden = arrArgv.includes("-a");
+
+const paths = arrArgv.filter((argv) => !argv.startsWith("-"));
+if (paths.length === 0) path = "[.]";
+
+for (let listFile of paths) {
+  const status = await fs.stat(listFile);
+
+  if (status.isFile()) {
+    const permissions = (status.mode & 0o777).toString(8);
+    const sizeFile = status.size;
+    const owner = status.uid;
+    const group = status.gid;
+    const timeMod = status.mtime.toLocaleString();
+
+    if (longFormat) {
+      console.log(
+        `${permissions}, ${owner}, ${group}, ${sizeFile}, ${timeMod}, ${listFile}`
+      );
+    } else {
+      console.log(listFile);
+    }
+  } else {
+    let files = await fs.readdir(listFile, { withFileTypes: true });
+
+    if (!showHidden) {
+      files = files.filter((file) => !file.name.startsWith("."));
+    }
+
+    for (let file of files) {
+      const wholePath = path.join(listFile, file.name);
+      const statusFile = await fs.stat(wholePath);
+
+      const permissions = (statusFile.mode & 0o777).toString(8);
+      const sizeFile = statusFile.size;
+      const owner = statusFile.uid;
+      const group = statusFile.gid;
+      const timeMod = statusFile.mtime.toLocaleString();
+
+      if (longFormat) {
+        console.log(
+          `${permissions}, ${owner}, ${group}, ${sizeFile}, ${timeMod}, ${file.name}`
+        );
+      } else {
+        console.log(file.name);
+      }
+    }
+  }
+}

implement-shell-tools/wc/wc.js

@@ -0,0 +1,38 @@
+import process from "node:process";
+import { promises as fs } from "node:fs";
+
+const arrArgv = process.argv.slice(2);
+
+const lines = arrArgv.includes("-l");
+const words = arrArgv.includes("-w");
+const bytes = arrArgv.includes("-c");
+
+const noFlags = !lines && !words && !bytes;
+
+const paths = arrArgv.filter((argv) => !argv.startsWith("-"));
+
+for (let path of paths) {
+  const context = await fs.readFile(path, "utf-8");
+
+  const countLines = context.split(/\r?\n/).length;
+  const countWords = context.split(/\s+/).length;
+  const countBytes = Buffer.byteLength(context, "utf-8");
+
+  let startInput = "";
+
+  if (noFlags || lines) {
+    startInput += `${countLines} `;
+  }
+
+  if (noFlags || words) {
+    startInput += `${countWords} `;
+  }
+
+  if (noFlags || bytes) {
+    startInput += `${countBytes} `;
+  }
+
+  startInput += path;
+
+  console.log(startInput);
+}