add ls.js file in

Author: pathywang

implement-shell-tools/ls/ls.js

@@ -0,0 +1,57 @@
+const fs = require("fs");
+const path = require("path");
+
+const args = process.argv.slice(2);
+
+let oneLine = false;
+let showHidden = false;
+let targets = [];
+
+for (const arg of args) {
+    if (arg === "-1") {
+        oneLine = true;
+    } else if (arg === "-a") {
+        showHidden = true;
+    } else {
+        targets.push(arg);
+    }
+}
+
+if (targets.length === 0) {
+    targets.push(".");
+}
+
+function listDirectory(directory) {
+    let files = fs.readdirSync(directory);
+
+    if (!showHidden) {
+        files = files.filter(file => !file.startsWith("."));
+    }
+
+    files.sort();
+
+    if (oneLine) {
+        console.log(files.join("\n"));
+    } else {
+        console.log(files.join("  "));
+    }
+}
+
+function listTarget(target) {
+    try {
+        const stats = fs.statSync(target);
+
+        if (stats.isDirectory()) {
+            listDirectory(target);
+        } else {
+            console.log(target);
+        }
+
+    } catch (error) {
+        console.error(`ls: cannot access '${target}': No such file or directory`);
+    }
+}
+
+for (const target of targets) {
+    listTarget(target);
+}