Function enterView

packages/core/src/render3/state.ts:634–658

(newView: LView)

 * @returns the previously active lView;
 */
export function enterView(newView: LView): void {
  ngDevMode && assertNotEqual(newView[0], newView[1] as any, '????');
  ngDevMode && assertLViewOrUndefined(newView);
  const newLFrame = allocLFrame();
  if (ngDevMode) {
    assertEqual(newLFrame.isParent, true, 'Expected clean LFrame');
    assertEqual(newLFrame.lView, null, 'Expected clean LFrame');
    assertEqual(newLFrame.tView, null, 'Expected clean LFrame');
    assertEqual(newLFrame.selectedIndex, -1, 'Expected clean LFrame');
    assertEqual(newLFrame.elementDepthCount, 0, 'Expected clean LFrame');
    assertEqual(newLFrame.currentDirectiveIndex, -1, 'Expected clean LFrame');
    assertEqual(newLFrame.currentNamespace, null, 'Expected clean LFrame');
    assertEqual(newLFrame.bindingRootIndex, -1, 'Expected clean LFrame');
    assertEqual(newLFrame.currentQueryIndex, 0, 'Expected clean LFrame');
  }
  const tView = newView[TVIEW];
  instructionState.lFrame = newLFrame;
  ngDevMode && tView.firstChild && assertTNodeForTView(tView.firstChild, tView);
  newLFrame.currentTNode = tView.firstChild!;
  newLFrame.lView = newView;
  newLFrame.tView = tView;
  newLFrame.contextLView = newView;
  newLFrame.bindingIndex = tView.bindingStartIndex;
  newLFrame.inI18n = false;
}

/**
 * Allocates next free LFrame. This function tries to reuse the `LFrame`s to lower memory pressure.