eyes-on.js

#!/usr/bin/env node

const fs = require('fs');
const chalk = require('chalk');
const Termparse = require('termparse');
const spawnSync = require('child_process').spawnSync;

var tp = new Termparse();

const banner = () => {
    let B = `
▒██▀░▀▄▀▒██▀░▄▀▀░▒░░▄▀▄░█▄░█
░█▄▄░▒█▒░█▄▄▒▄██░▀▀░▀▄▀░█▒▀█
`
    console.log(chalk.greenBright(B));

}

//args is list of files(not flags/options)
var filter_files = function (args) {
    var file_info_list = new Object();
    var found_files = "";
    var not_found_files = "";
    args.map(f => {
        if (fs.existsSync(f)) {
            file_info_list[f] = new Object();
            file_info_list[f].exists = true;
            file_info_list[f].modified = false;
            file_info_list[f].exists = true;
            file_info_list[f].mod_time_ms = fs.statSync(f).mtimeMs;
            file_info_list[f].mod_time = fs.statSync(f).mtime;
            found_files += ` ${f}`; //update found files list
        } else {
            not_found_files += ` ${f}`; //update not found files list
        }
    });
    if (found_files.length > 0) console.log(chalk.black.bgYellowBright(`FOUND`), chalk.underline(found_files));

    if (not_found_files.length > 0) {
        console.log(chalk.whiteBright.bgRed(`NOT FOUND`), chalk.underline(not_found_files));
        console.log(chalk.red.italic('\nfiles are missing among the files passed.'));
        console.log(chalk.red('exiting...'));
        process.exit();
    }

    return file_info_list;
}


//checks for modified file and gives signal
var onChange = (f, file_info_list) => {
    if (fs.existsSync(f)) {
        var f_info = fs.statSync(f);
        if (file_info_list[f].mod_time_ms !== f_info.mtimeMs) {
            file_info_list[f].mod_time_ms = f_info.mtimeMs;
            file_info_list[f].mod_time = f_info.mtime;
            file_info_list[f].exists = true;
            file_info_list[f].modified = true;
        } else {
            file_info_list[f].modified = false;
        }
    } else {
        file_info_list[f].exists = false;
    }
    return file_info_list;
}

//TODO: detect exit key and give options
//takes string as input=> splits based on line break => splits based on spaces 
var commandExec = function (raw_cmd) {
    let cmds = raw_cmd.split('\n');
    for (c of cmds) {
        if (c.length > 0) {
            let p_cmd = c.split(" ");
            var cmd_res = spawnSync(p_cmd[0], p_cmd.slice(1), { encoding: 'utf8' });

            if (cmd_res.stderr.length > 0) {
                console.log(chalk.blueBright("executing command..."));
                console.log(chalk.whiteBright.bgRed.underline("ERR:"), "\n", cmd_res.stderr);
                console.log(chalk.yellow("waiting for changes in file"));
                break;
            }
            if (cmd_res.stdout.length > 0) {
                console.log(chalk.blueBright("executing command..."));
                console.log(chalk.black.bgYellowBright.underline(c), "\n", cmd_res.stdout);
                console.log(chalk.blueBright("command exected"));
            }
        }
    }
}

//calls onChange() => receives signal => gives appropriate message
//cmd_list :string
var watch = (file_info_list, cmd_list) => {
    if (Object.keys(file_info_list).length === 0) {
        console.log(chalk.redBright.italic(`\nno files left to watch`));
        console.log(chalk.redBright('exiting...'));
        process.exit();
    }
    for (file in file_info_list) {
        file_info_list = onChange(file, file_info_list);
        mod_time = file_info_list[file].mod_time;
        if (!file_info_list[file].exists) {
            console.log("\n---------------------------------------------");
            console.log(`${mod_time} :: ${file} :: ${chalk.yellowBright.bold('DELETED')}`);
            delete file_info_list[file];
            console.log("---------------------------------------------\n");
        } else if (file_info_list[file].modified) {
            console.log("\n---------------------------------------------");
            console.log(`${mod_time} :: ${file} :: ${chalk.blueBright.bold('MODIFIED')}`);
            commandExec(cmd_list);
            console.log("---------------------------------------------\n");
        }
    }
}

/******************** driver code **************************/

//command: watch => watches over one or multiple files
tp.addCommand({
    name: "watch",
    usage: "used to watch over one or multiple file",
    run: function () {
        if (tp.args.length === 0) {
            console.log(chalk.red("no file name or pattern passed"));
            process.exit();
        }

        let exec_command = this.getFlag('c');
        let time_interval = this.getFlag('t');

        banner();
        console.log(chalk.green.bold('starting...'));
        let file_list = filter_files(tp.args);
        console.log(chalk.greenBright.bold('watching...'));
        setInterval(() => {
            watch(file_list, exec_command.value);
        }, parseInt(time_interval.value));
    }
}).setFlags({
    name: "t",
    type: "number",
    value: 2000,
    usage: "takes time in milliseconds as input to set the watch interval (default: 2000ms/2s )"
}, {
    name: "c",
    type: "string",
    value: "",
    usage: "takes one or multiple commands and executes on modification of file"
})


var args = process.argv.slice(2);
tp.parse(args); //parsing args and executing appropriate command