build.js

let esbuild = require("esbuild");
const path = require("path");

let entries = {
  modals: "./static/js/modals/index.js",
};

const isDev = process && process.env && process.env.NODE_ENV === "development";

for (const [key, value] of Object.entries(entries)) {
  const options = {
    entryPoints: [value],
    bundle: true,
    minify: !isDev,
    nodePaths: [path.resolve(__dirname, "./static/js/src")],
    sourcemap: !isDev,
    outfile: "static/js/" + key + ".js",
    target: ["chrome90", "firefox88", "safari14", "edge90"],
    define: {
      "process.env.NODE_ENV":
        // Explicitly check for 'development' so that this defaults to
        // 'production' in all other cases.
        isDev ? '"development"' : '"production"',
    },
  };

  esbuild
    .build(options)
    .then((result) => {
      console.log("Built " + key + ".js");
    })
    // Fail the build if there are errors.
    .catch(() => process.exit(1));
}