Image resize script

resize

#!/usr/bin/env node

const color = require('cli-color');
const Jimp = require('jimp');

const [inputFile, resizeInput, outputFile] = process.argv.slice(2);

const usage = () => {
  console.log(
    color.red(
      `Usage: resize [input-file] [[width]x[height]|[percent]%] <output-file>`
    )
  );

  process.exit(1);
};

const isNumeric = value => String(Number(value)) === String(value);

const scaleByPercentage = (image, input) => {
  const amount = Number(input.slice(0, -1)) / 100;

  if (!isNumeric(amount)) {
    throw new Error(`Invalid scale amount: ${amount}`);
  }

  return image.scale(amount);
};

const resizeWithBothSides = (image, input) => {
  const sizes = input.split('x');
  const [sizeX, sizeY] = sizes;

  if (sizes.length !== 2 || !isNumeric(sizeX) || !isNumeric(sizeY)) {
    throw new Error('Invalid resize amounts');
  }

  return image.resize(Number(sizeX), Number(sizeY));
};

const run = async () => {
  if (!inputFile || !resizeInput) {
    return usage();
  }

  const image = await Jimp.read(inputFile);

  if (resizeInput.endsWith('%')) {
    // e.g. `50%`
    scaleByPercentage(image, resizeInput);
  } else if (resizeInput.includes('x')) {
    // e.g. `200x150`
    resizeWithBothSides(image, resizeInput);
  } else {
    throw new Error('Invalid resize amounts');
  }

  image.quality(100);

  await image.writeAsync(outputFile || inputFile);

  console.log(`${color.green('✓')} Saved resized to ${outputFile}`);
};

return run();