compositeImage.js

const imagemagick = require('imagemagick');
const rootPath = require('app-root-path');

const compositeImage = async (imageName, imageList) => new Promise((resolve, reject) => {
  try {
    const commands = [imageList[0]];
    for (let i = 1; i < imageList.length; i += 1) {
      commands.push('-coalesce', 'null:', imageList[i], '-layers', 'composite');
    }
    commands.push(`${rootPath}/images/${imageName}.png`);

    imagemagick.convert(commands, (error, result) => {
      if (error) {
        console.error(error);
        reject(error);
      } else {
        console.log(result);
        resolve(`${rootPath}/images/${imageName}.png`);
      }
    });
  } catch (error) {
    reject(error);
  }
});