Watch and build code with esbuild

esbuild-dev.ts

import { startService } from "esbuild";
import { watch } from "chokidar";

const noop = () => {};

/**
 * Function to update lines when something happens
 * @param input The text you want to print
 * @param isBuiltInput Whether you are printing `Built in x ms` or not
 */
const updateLine = (input: string, isBuiltInput: boolean = false) => {
  const numberOfLines = (input.match(/\n/g) || []).length;
  process.stdout.cursorTo(0, 2);
  process.stdout.clearScreenDown();
  process.stdout.write(input);
  isBuiltInput ? process.stdout.moveCursor(0, -numberOfLines) : noop();
};

/**
 * Builds the code in no time
 */
const build = async () => {
  //Start build service
  const service = await startService();
  try {
    process.stdout.cursorTo(0, 2);
    process.stdout.clearLine(0);
    // Get time before build starts
    const timerStart = Date.now();
    // Build code
    await service.build({
      color: true,
      entryPoints: ["./src/index.ts"],
      outfile: "./lib/index.js",
      // minify: true,
      bundle: true,
      sourcemap: false,
      tsconfig: "./tsconfig.json",
      platform: "node",
      logLevel: "error",
    });
    // Get time after build ends
    const timerEnd = Date.now();
    updateLine(`Built in ${timerEnd - timerStart}ms.`, true);
  } catch (e) {
    // OOPS! ERROR!
  } finally {
    // We command you to stop. Will start again if files change.
    service.stop();
  }
};

const watcher = watch(["src/**/*"]);
console.log("Watching files... \n");
build();
watcher.on("change", () => {
  build();
});