index.js

const { stat, readFile } = require("fs").promises;
const defLimit = "10000";
function escapeRegExp(string) {
  // $& means the whole matched string
  return string.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
}
let initCounter = 0;
module.exports = (options = {}) => {
  // if user initializes the plugin more than one times (ie. different size for every extension),
  // use different name to prevent collisions
  initCounter++;

  return {
    name: `inline-image${initCounter > 1 ? `#${initCounter - 1}` : ""}`,
    setup(build) {
      const limit =
        typeof options.limit === "string" || typeof options.limit === "number"
          ? options.limit === 0 || options.limit === ""
            ? 0
            : options.limit === -1 || options.limit === "-1"
            ? -1
            : parseInt(options.limit, 10) ||
              parseInt(process.env.IMAGE_INLINE_SIZE_LIMIT || defLimit, 10) ||
              parseInt(defLimit, 10)
          : typeof options.limit === "function"
          ? options.limit
          : typeof options.limit === "undefined"
          ? parseInt(process.env.IMAGE_INLINE_SIZE_LIMIT || defLimit, 10) ||
            parseInt(defLimit, 10)
          : 0;
      const extensions =
        typeof options.extensions === "object" &&
        Array.isArray(options.extensions)
          ? options.extensions
          : ["svg", "png", "jpeg", "jpg", "gif", "webp", "avif"];
      const filter =
        typeof options.filter === "object" && options.filter instanceof RegExp
          ? options.filter
          : extensions.length > 0
          ? new RegExp(
              `\\.(${extensions
                .map((x) => x && escapeRegExp(x.replace(".", "")))
                .filter(Boolean)
                .join("|")})$`
            )
          : null;
      const namespace =
        typeof options.namespace === "string" ? options.namespace : undefined;
      if (limit && filter) {
        build.onLoad({ filter, namespace }, async (args) => {
          let contents;
          let loader = "file";
          if (limit === -1) {
            contents = await readFile(args.path);
            loader = "dataurl";
          } else if (typeof limit === "function") {
            const r = limit(args);
            if (
              (typeof r === "object" && r instanceof Promise && (await r)) ||
              (typeof r === "boolean" && r)
            ) {
              contents = await readFile(args.path);
              loader = args.loader || "dataurl";
            }
          } else {
            const stats = await stat(args.path);
            if (stats && stats.size < limit) {
              contents = await readFile(args.path);
              loader = "dataurl";
            }
          }
          return {
            contents,
            loader,
          };
        });
      }
      if (options.loaderRegisterExtensions !== false && extensions.length > 0) {
        const esbuildOptions = build.initialOptions;
        if (typeof esbuildOptions.loader !== "object") {
          esbuildOptions.loader = {};
        }
        extensions.forEach((ext) => {
          if (ext) {
            esbuildOptions.loader[`.${ext.replace(".", "")}`] = "file";
          }
        });
      }
    },
  };
};