task: complete implementation of ls functionality in javascript

Author: XiaoQuark

implement-shell-tools/ls/ls.mjs

@@ -0,0 +1,110 @@
+import process from "node:process";
+import fs, { truncate } from "node:fs";
+
+const argv = process.argv.slice(2);
+
+const options = {
+	onePerLine: false,
+	all: false,
+	help: false,
+};
+
+const validFlags = {
+	onePerLine: {
+		short: "-1",
+		long: "--one-per-line",
+		description: "Lists one file per line",
+	},
+	all: {
+		short: "-a",
+		long: "--all",
+		description: "Include entries whose names begin with a dot",
+	},
+	help: {
+		short: "-h",
+		long: "--help",
+		description: "Display help information",
+	},
+};
+
+const paths = [];
+let parsingFlags = true;
+
+for (const arg of argv) {
+	if (arg === "--") {
+		parsingFlags = false;
+	} else if (parsingFlags && arg.startsWith("--")) {
+		const matchedFlag = Object.entries(validFlags).find(
+			([, definition]) => arg === definition.long,
+		);
+
+		if (matchedFlag) {
+			const [optionName] = matchedFlag;
+			options[optionName] = true;
+		} else {
+			process.stderr.write(`Invalid option -- '${arg}'\n`);
+			process.exit(1);
+		}
+	} else if (parsingFlags && arg.startsWith("-")) {
+		const shortFlags = arg.slice(1);
+
+		for (const shortFlag of shortFlags) {
+			const matchedFlag = Object.entries(validFlags).find(
+				([, definition]) => definition.short === `-${shortFlag}`,
+			);
+
+			if (matchedFlag) {
+				const [optionName] = matchedFlag;
+				options[optionName] = true;
+			} else {
+				process.stderr.write(`Invalid option -- '${arg}\n'`);
+				process.exit(1);
+			}
+		}
+	} else {
+		paths.push(arg);
+	}
+}
+
+if (paths.length === 0) {
+	paths.push(".");
+}
+
+const multiplePaths = paths.length > 1;
+const filePaths = [];
+const directoryPaths = [];
+
+for (const path of paths) {
+	const stats = fs.statSync(path);
+
+	if (stats.isDirectory()) {
+		directoryPaths.push(path);
+	} else {
+		filePaths.push(path);
+	}
+}
+
+if (filePaths.length > 0) {
+	const separator = options.onePerLine ? "\n" : "  ";
+	process.stdout.write(`${filePaths.join(separator)}\n`);
+}
+
+for (const path of directoryPaths) {
+	if (multiplePaths) {
+		process.stdout.write(`\n${path}: \n`);
+	}
+	let content = fs.readdirSync(path);
+
+	if (options.all) {
+		content.unshift(".", "..");
+	} else {
+		content = content.filter((entry) => !entry.startsWith("."));
+	}
+
+	content.sort();
+
+	const separator = options.onePerLine ? "\n" : "  ";
+	const output = content.join(separator);
+
+	process.stdout.write(`${output}\n`);
+}