Function cacheState

test/angular/1.7/angular.js:6686–6698

()

  // This variable should be used *only* inside the cacheState function.
  var lastCachedState = null;
  function cacheState() {
    // This should be the only place in $browser where `history.state` is read.
    cachedState = getCurrentState();
    cachedState = isUndefined(cachedState) ? null : cachedState;

    // Prevent callbacks fo fire twice if both hashchange & popstate were fired.
    if (equals(cachedState, lastCachedState)) {
      cachedState = lastCachedState;
    }

    lastCachedState = cachedState;
    lastHistoryState = cachedState;
  }

  function fireStateOrUrlChange() {
    var prevLastHistoryState = lastHistoryState;