gistfile1.txt

"use strict";

var {unload} = require("unload+");

/**
 * Helper that adds event listeners and remembers to remove on unload
 */
exports.listen = function listen(window, node, event, func, capture) {
  // Default to use capture
  if (capture == null)
    capture = true;

  node.addEventListener(event, func, capture);
  function undoListen() {
    node.removeEventListener(event, func, capture);
  }

  // Undo the listener on unload and provide a way to undo everything
  let undoUnload = unload(undoListen, window);
  return function() {
    undoListen();
    undoUnload();
  };
}