@testdeck/mocha/bin/watch

#!/usr/bin/env node
// Run "tsc" with watch, upon successful compilation run mocha tests.

const chalk = require("chalk");
const spawn = require("cross-spawn");
const readline = require("readline");
const yargs = require("yargs");
const fs = require("fs");

const argv = yargs
  .options({
      p: {
          alias: "project",
          demand: false,
          default: ".",
          describe: "Path to tsconfig file or directory containing tsconfig, passed to `tsc -p <value>`.",
          type: "string",
      },
      t: {
          alias: "tsc",
          demand: false,
          default: "tsc",
          describe: "Path to executable tsc, by default points to typescript installed as dependency, then to global tsc installation.",
          type: "string",
      },
      o: {
          alias: "opts",
          demand: false,
          default: "./test/mocha.opts",
          describe: "Path to mocha.opts file containing additional mocha configuration.",
          type: "string",
      },
      m: {
          alias: "mocha",
          demand: false,
          default: "mocha",
          describe: "Path to executable mocha, by default points to mocha installed as dependency, then to global mocha installation.",
          type: "string",
      },
      n: {
          alias: "times",
          demand: false,
          default: undefined,
          describe: "Number of iterations before the watcher process quits. For testing purposes only.",
          type: "number",
      },
      g: {
          alias: "grep",
          demand: false,
          default: undefined,
          describe: "Passed down to mocha: only run tests matching <pattern>",
          type: "string",
      },
      f: {
          alias: "fgrep",
          demand: false,
          default: undefined,
          describe: "Passed down to mocha: only run tests containing <string>",
          type: "string",
      },
  })
  .help("h")
  .alias("h", "help")
  .argv;

const stdl = readline.createInterface({ input: process.stdin });
stdl.on("line", (line) => {
    // TODO: handle "g <pattern>" or "f <pattern>" to run mocha with pattern
    // Ctrl + R may restart mocha test run?
});

let mochap = null;
let errors = 0;

function compilationStarted() {
    if (mochap) {
        mochap.kill("SIGINT");
    }
    mochap = null;
    errors = 0;
}
function foundErrors() {
    errors ++;
}
function compilationComplete() {
    if (errors) {
        console.log(chalk.red("TS errors!"));
        return;
    } else {
        console.log(chalk.gray("Run mocha."));
    }

    const mochaOptions = ["--colors"].concat(argv._);
    if (argv.opts && fs.existsSync(argv.opts)) {
        mochaOptions.push("--opts");
        mochaOptions.push(argv.opts);
    }
    if (argv.g) {
        mochaOptions.push("-g");
        mochaOptions.push(argv.g);
    }
    if (argv.f) {
        mochaOptions.push("-f");
        mochaOptions.push(argv.f);
    }
    mochap = spawn(argv.mocha, mochaOptions);
    mochap.on("close", (code) => {
        if (mochap) {
            if (code) {
                console.log(chalk.red("Exited with " + code));
            } else {
            }
            if (argv.times && (times >= argv.times)) {
                tscp.kill("SIGINT");
            }
            mochap = null;
        }
    });
    mochap.stdout.on("data", (chunk) => {
        // Ensure old processes won't interfere tsc, .pipe here may be good enough.
        if (mochap) {
            process.stdout.write(chunk);
        }
    });
    mochap.stderr.on("data", (chunk) => {
        // Ensure old processes won't interfere tsc, .pipe here may be good enough.
        if (mochap) {
            process.stderr.write(chunk);
        }
    });
}

const tscp = spawn(argv.tsc, ["-p", argv.project, "-w"]);
const tscl = readline.createInterface({ input: tscp.stdout });
let times = 0;
tscl.on("line", (line) => {
    if (line.indexOf("Compilation complete.") >= 0 || line.indexOf("Found ") >= 0) {
        console.log(line);
        times++;
        compilationComplete();
    } else if (line.indexOf("File change detected.") >= 0) {
        compilationStarted();
        console.log(line);
    } else if (line.indexOf(": error TS") >= 0) {
        console.log(line);
        foundErrors();
    }
});

tscl.on("close", () => {
    stdl.close();
    tscl.close();
});