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Key navigation

To be used for mapping keyboard arrow press events

As of 02. 10. 2022. See the latest version.

This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greatest.deepsurf.us/scripts/396703/1100259/Key%20navigation.js 

(() => {
  'use strict';

  const setUpKeyNavigation = ({
    onDownPressed,
    onLeftPressed,
    onRightPressed,
    onUpPressed,
    preventDefault,
    stopPropagation,
  }) => {
    document.addEventListener('keydown', (event) => {
      const operation = {
        ArrowDown: (e) => executeFn(onDownPressed, e),
        ArrowLeft: (e) => executeFn(onLeftPressed, e),
        ArrowRight: (e) => executeFn(onRightPressed, e),
        ArrowUp: (e) => executeFn(onUpPressed, e),
      }[event.key];

      if (operation) operation(event);

      preventDefault && event.preventDefault();
      stopPropagation && event.stopPropagation();
    });
  };

  const setUpAnchorNavigation = (selectorsMap) => {
    const downHref = getAnchorHref(selectorsMap.down);
    const leftHref = getAnchorHref(selectorsMap.left);
    const rightHref = getAnchorHref(selectorsMap.right);
    const upHref = getAnchorHref(selectorsMap.up);

    setUpKeyNavigation({
      onDownPressed: generateNavigationEvent(downHref),
      onLeftPressed: generateNavigationEvent(leftHref),
      onRightPressed: generateNavigationEvent(rightHref),
      onUpPressed: generateNavigationEvent(upHref),
    });
  };

  const getElement = (selector) => {
    return selector ? document.querySelector(selector) : undefined;
  };

  const getAnchorHref = (selector) => {
    return getElement(selector)?.href;
  };

  const generateNavigationEvent = (href) => {
    return href ? () => (location.href = href) : undefined;
  };

  const executeFn = (fn, ...parameters) => {
    return typeof fn === 'function' && fn(...parameters);
  };

  window.setUpAnchorNavigation = setUpAnchorNavigation;
  window.setUpKeyNavigation = setUpKeyNavigation;
})();