server/node_modules/@jimp/plugin-invert/src/index.js

import { isNodePattern } from "@jimp/utils";

/**
 * Inverts the image
 * @param {function(Error, Jimp)} cb (optional) a callback for when complete
 * @returns {Jimp} this for chaining of methods
 */
export default () => ({
  invert(cb) {
    this.scanQuiet(
      0,
      0,
      this.bitmap.width,
      this.bitmap.height,
      function (x, y, idx) {
        this.bitmap.data[idx] = 255 - this.bitmap.data[idx];
        this.bitmap.data[idx + 1] = 255 - this.bitmap.data[idx + 1];
        this.bitmap.data[idx + 2] = 255 - this.bitmap.data[idx + 2];
      }
    );

    if (isNodePattern(cb)) {
      cb.call(this, null, this);
    }

    return this;
  },
});