Deno script for creating optimized images for the web and and their metadata

deno_img_opt.js

import { Image } from "https://deno.land/x/imagescript@1.2.15/mod.ts";
import { join } from "https://deno.land/std@0.220.0/path/mod.ts";

const inputDir = join(Deno.cwd(), "src", "assets", "img", "gallery");
const outputDir = join(Deno.cwd(), "src", "assets", "img", "gallery-opt");

const imagesObjsArr = [];

/**
 * Optimizes the images in the inputDir directory and saves them to the outputDir directory
 * writes the optimized images metadata to a images.ts file in the outputDir directory
 * 
 */
async function optimizeImages() {
    const files = [];

    for await (const dirEntry of Deno.readDir(inputDir)) {
      if (dirEntry.isFile) {
        files.push(dirEntry.name);
      }
    }

    const images = files.filter(file => /\.(jpg|jpeg|png|webp|gif)$/i.test(file));
    for(let img of images) {
        const imgData = await optimizeImgForWeb(`${inputDir}/${img}`, `${outputDir}/${img}`, 70, img)
        imagesObjsArr.push(imgData)
    }

    const content = `export const images = ${JSON.stringify(imagesObjsArr)}`;
    await Deno.writeTextFile(outputDir+'/images.ts', content);
}

/**
 * Optimizes an image for the web in jpg format
 * @param {*} inputPath 
 * @param {*} outputPath 
 * @param {*} quality 
 * @param {*} fileName 
 * @returns JSON object with image metadata
 */
async function optimizeImgForWeb(inputPath, outputPath, quality = 70, fileName) {
  try {
    // Read the input file
    const inputBuffer = await Deno.readFile(inputPath);

    // Decode the image
    const image = await Image.decode(inputBuffer);
    image.resize(1000, Image.RESIZE_AUTO);

    const outputImg = await image.encodeJPEG(quality);
    
    await Deno.writeFile(outputPath, outputImg);

    const obj = {
      name: fileName,
      width: image.width,
      height: image.height
    }

    return obj;
  } catch (error) {
    console.error(`Error converting ${inputPath} to Optimized file:`, error);
  }
}

if (import.meta.main) {
    console.log(`Optimizing images please wait...`);
    const t0 = performance.now();
    await optimizeImages();
    const t1 = performance.now();
    console.log(`Optimized ${imagesObjsArr.length} images in ${t1 - t0} milliseconds.`);
}