compress_images.js

const { spawn } = require("child_process");
const { promises: fs } = require("fs");
const path = require("path");

const GUETZLI_EXEC = "C:\\ProgramData\\chocolatey\\bin\\guetzli.EXE";
const MAGICK_EXEC = "C:\\ProgramData\\chocolatey\\bin\\magick.EXE";

// const sizes = [190, 290, 415, 830, 1125];
// const sizes = [612];
const sizes = [317, 830];

const sources = ["*.jpg"];

const promisesCompression = [];

for (const size of sizes) {
  const dirPath = path.join(".", size + "w");
  promisesCompression.push(
    fs
      .mkdir(dirPath)
      .catch(() =>
        fs
          .readdir(dirPath)
          .then(dir =>
            Promise.all(
              dir.map(fileName => fs.unlink(path.join(dirPath, fileName)))
            )
          )
      )
      .then(
        () =>
          new Promise((resolve, reject) => {
            const childProcess = spawn(MAGICK_EXEC, [
              "mogrify",
              "-resize",
              size,
              "-path",
              size + "w",
              "-format",
              "png",
              ...sources,
            ]);
            childProcess.stdout.pipe(process.stdout);
            childProcess.stderr.pipe(process.stderr);

            childProcess.on("error", err =>
              reject(console.error(size + "w fails", err))
            );
            childProcess.on("close", errorCode => {
              if (errorCode) {
                console.error(size + "w fails", errorCode);
                reject();
              } else {
                console.log(size + "w resizing succeeds");
                resolve();
              }
            });
          })
      )
      .then(() => fs.readdir(dirPath))
      .then(dir =>
        Promise.all(
          dir.filter(fileName => fileName.endsWith(".png")).map(
            fileName =>
              new Promise((resolve, reject) => {
                const childProcess = spawn(GUETZLI_EXEC, [
                  path.join(dirPath, fileName),
                  path.join(dirPath, fileName.replace(/png$/, "jpg")),
                ]);

                childProcess.stdout.pipe(process.stdout);
                childProcess.stderr.pipe(process.stderr);

                childProcess.on("error", err =>
                  reject(console.error(fileName + " " + size + "w fails", err))
                );
                childProcess.on("close", errorCode => {
                  if (errorCode) {
                    console.error(fileName + " " + size + "w fails", errorCode);
                    reject();
                  } else {
                    console.log(fileName + " " + size + "w succeeds");
                    resolve(Date.now());
                  }
                });
              })
          )
        )
      )
      .then(all =>
        fs
          .readdir(dirPath)
          .then(dir =>
            Promise.all(
              dir
                .filter(fileName => fileName.endsWith(".png"))
                .map(fileName => fs.unlink(path.join(dirPath, fileName)))
            ).then(() => all)
          )
      )
  );
}

Promise.all(promisesCompression).then(console.log, console.error);