cat.js

import process from "node:process";
import {promises as fs} from "node:fs";
import {program} from "commander";

program
    .name("display-file-content")
    .description("Output the content of a file to the terminal")
    .argument("<path...>", "The file path to process")
    .option("-n", "Number the output lines")
    .option("-b","Number the non-blank output lines")

program.parse();

const paths = program.args;

const options = program.opts();

let lineNumber = 1;

for (const path of paths) {
    const filesContent = await fs.readFile(path, "utf-8");

    const lines = filesContent.split("\n");

    if (lines[lines.length - 1] === "") {
        lines.pop();
    }

    for (let line of lines) {
    if (options.n) {
        process.stdout.write(`${lineNumber}  ${line}\n`);
        lineNumber++;
    } else if (options.b) {
        if (line != "") {
        process.stdout.write(`${lineNumber}  ${line}\n`);
        lineNumber++;
        } else {
        process.stdout.write("\n");
        }
    } else {
        process.stdout.write(line + "\n");
    }
    }
}