react-native-autopilot/lib/applyNavigatorChanges.js

Automatically push and pop navigator routes/scenes/screens if the navigator props was changed.

function defaultCompareRoute(routeA, routeB) {
  return routeA === routeB;
}

export default function applyNavigatorChanges(
  prevRouteStack, nextRouteStack, navigator, compareRoute = defaultCompareRoute) {
  if (!prevRouteStack || !prevRouteStack.length) {
    throw new Error('Prev route stack must be an array with at least one entry!');
  } else if (!nextRouteStack || !nextRouteStack.length) {
    throw new Error('Next route stack must be an array with at least one entry!');
  } else if (!navigator) {
    throw new Error('Navigator must be defined!');
  }

  if (prevRouteStack === nextRouteStack) {
    return;
  }

  if (!compareRoute(prevRouteStack[0], nextRouteStack[0])) {
    navigator.immediatelyResetRouteStack(nextRouteStack);
    return;
  }

  if (prevRouteStack.length < nextRouteStack.length) {
    // Maybe we should add (push) some new routes!
    for (let i = 0; i < prevRouteStack.length; i++) {
      if (!compareRoute(prevRouteStack[i], nextRouteStack[i])) {
        navigator.replaceAtIndex(nextRouteStack[i], i);
      }
    }
    for (let j = prevRouteStack.length; j < nextRouteStack.length; j++) {
      navigator.push(nextRouteStack[j]);
    }
  } else if (prevRouteStack.length > nextRouteStack.length) {
    // Maybe we should remove (pop) some new routes!
    for (let k = 0; k < nextRouteStack.length; k++) {
      if (!compareRoute(prevRouteStack[k], nextRouteStack[k])) {
        navigator.replaceAtIndex(nextRouteStack[k], k);
      }
    }
    for (let l = nextRouteStack.length; l < prevRouteStack.length; l++) {
      navigator.pop();
    }
  } else {
    // Maybe we should replace some new routes!
    for (let m = 0; m < prevRouteStack.length; m++) {
      if (!compareRoute(prevRouteStack[m], nextRouteStack[m])) {
        navigator.replaceAtIndex(nextRouteStack[m], m);
      }
    }
  }
}