pngjs/lib/filter-parse-sync.js

let SyncReader = require("./sync-reader");
let Filter = require("./filter-parse");

exports.process = function (inBuffer, bitmapInfo) {
  let outBuffers = [];
  let reader = new SyncReader(inBuffer);
  let filter = new Filter(bitmapInfo, {
    read: reader.read.bind(reader),
    write: function (bufferPart) {
      outBuffers.push(bufferPart);
    },
    complete: function () {},
  });

  filter.start();
  reader.process();

  return Buffer.concat(outBuffers);
};