Function createEffect

test/neverland.js:439–489

(sync)

  var stop = function stop() {};

  var createEffect = function createEffect(sync) {
    return function (effect, guards) {
      var state = current();
      var i = state.i++;
      var hook = state.hook,
          stack = state.stack,
          after = state.after;

      if (i < stack.length) {
        var info = stack[i];
        var clean = info.clean,
            update = info.update,
            values = info.values;

        if (!guards || guards.some(different, values)) {
          info.values = guards;

          if (clean) {
            info.clean = null;
            clean();
          }

          var invoke = function invoke() {
            info.clean = effect();
          };

          if (sync) after.push(invoke);else update(invoke);
        }
      } else {
        if (!effects.has(hook)) effects.set(hook, {
          stack: [],
          update: reraf()
        });
        var details = effects.get(hook);
        var _info = {
          clean: null,
          stop: stop,
          update: details.update,
          values: guards
        };
        stack[i] = _info;
        details.stack.push(_info);

        var _invoke = function _invoke() {
          _info.clean = effect();
        };

        if (sync) after.push(_invoke);else _info.stop = details.update(_invoke);
      }
    };
  };

  var useEffect = createEffect(false);
  var useLayoutEffect = createEffect(true);