react-native/Libraries/NavigationExperimental/NavigationStateUtils.js

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/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* @providesModule NavigationStateUtils
* @flow
*/
'use strict';
const invariant = require('fbjs/lib/invariant');
import type {
NavigationRoute,
NavigationState,
} from 'NavigationTypeDefinition';
function getParent(state: NavigationState): ?NavigationState {
if (
(state instanceof Object) &&
(state.routes instanceof Array) &&
(state.routes[0] !== undefined) &&
(typeof state.index === 'number') &&
(state.routes[state.index] !== undefined)
) {
return state;
}
return null;
}
function get(state: NavigationState, key: string): ?NavigationRoute {
const parentState = getParent(state);
if (!parentState) {
return null;
}
const childState = parentState.routes.find(child => child.key === key);
return childState || null;
}
function indexOf(state: NavigationState, key: string): ?number {
const parentState = getParent(state);
if (!parentState) {
return null;
}
const index = parentState.routes.map(child => child.key).indexOf(key);
if (index === -1) {
return null;
}
return index;
}
function push(state: NavigationState, newChildState: NavigationRoute): NavigationState {
var lastChildren: Array<NavigationRoute> = state.routes;
return {
...state,
routes: [
...lastChildren,
newChildState,
],
index: lastChildren.length,
};
}
function pop(state: NavigationState): NavigationState {
const lastChildren = state.routes;
return {
...state,
routes: lastChildren.slice(0, lastChildren.length - 1),
index: lastChildren.length - 2,
};
}
function reset(state: NavigationState, nextChildren: ?Array<NavigationRoute>, nextIndex: ?number): NavigationState {
const parentState = getParent(state);
if (!parentState) {
return state;
}
const routes = nextChildren || parentState.routes;
const index = nextIndex == null ? parentState.index : nextIndex;
if (routes === parentState.routes && index === parentState.index) {
return state;
}
return {
...parentState,
routes,
index,
};
}
function set(state: ?NavigationState, key: string, nextChildren: Array<NavigationRoute>, nextIndex: number): NavigationState {
if (!state) {
return {
routes: nextChildren,
index: nextIndex,
key,
};
}
const parentState = getParent(state);
if (!parentState) {
return {
routes: nextChildren,
index: nextIndex,
key,
};
}
if (nextChildren === parentState.routes && nextIndex === parentState.index && key === parentState.key) {
return parentState;
}
return {
...parentState,
routes: nextChildren,
index: nextIndex,
key,
};
}
function jumpToIndex(state: NavigationState, index: number): NavigationState {
const parentState = getParent(state);
if (parentState && parentState.index === index) {
return parentState;
}
return {
...parentState,
index,
};
}
function jumpTo(state: NavigationState, key: string): NavigationState {
const parentState = getParent(state);
if (!parentState) {
return state;
}
const index = parentState.routes.indexOf(parentState.routes.find(child => child.key === key));
invariant(
index !== -1,
'Cannot find child with matching key in this NavigationRoute'
);
return {
...parentState,
index,
};
}
function replaceAt(state: NavigationState, key: string, newState: NavigationState): NavigationState {
const parentState = getParent(state);
if (!parentState) {
return state;
}
const routes = [...parentState.routes];
const index = parentState.routes.indexOf(parentState.routes.find(child => child.key === key));
invariant(
index !== -1,
'Cannot find child with matching key in this NavigationRoute'
);
routes[index] = newState;
return {
...parentState,
routes,
};
}
function replaceAtIndex(state: NavigationState, index: number, newState: NavigationState): NavigationState {
const parentState = getParent(state);
if (!parentState) {
return state;
}
const routes = [...parentState.routes];
routes[index] = newState;
return {
...parentState,
routes,
};
}
const NavigationStateUtils = {
getParent,
get: get,
indexOf,
push,
pop,
reset,
set: set,
jumpToIndex,
jumpTo,
replaceAt,
replaceAtIndex,
};
module.exports = NavigationStateUtils;