expo-router
Version:
Expo Router is a file-based router for React Native and web applications.
153 lines • 6.42 kB
JavaScript
'use client';
;
var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
var desc = Object.getOwnPropertyDescriptor(m, k);
if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
desc = { enumerable: true, get: function() { return m[k]; } };
}
Object.defineProperty(o, k2, desc);
}) : (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
o[k2] = m[k];
}));
var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
Object.defineProperty(o, "default", { enumerable: true, value: v });
}) : function(o, v) {
o["default"] = v;
});
var __importStar = (this && this.__importStar) || function (mod) {
if (mod && mod.__esModule) return mod;
var result = {};
if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
__setModuleDefault(result, mod);
return result;
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.useFocusEffect = void 0;
// A fork of `useFocusEffect` that waits for the navigation state to load before
// running the effect. This is especially useful for native redirects.
const React = __importStar(require("react"));
const useLoadedNavigation_1 = require("./link/useLoadedNavigation");
/**
* Hook to run an effect whenever a route is **focused**. Similar to
* [`React.useEffect`](https://react.dev/reference/react/useEffect).
*
* This can be used to perform side-effects such as fetching data or subscribing to events.
* The passed callback should be wrapped in [`React.useCallback`](https://react.dev/reference/react/useCallback)
* to avoid running the effect too often.
*
* @example
* ```tsx
* import { useFocusEffect } from 'expo-router';
* import { useCallback } from 'react';
*
* export default function Route() {
* useFocusEffect(
* // Callback should be wrapped in `React.useCallback` to avoid running the effect too often.
* useCallback(() => {
* // Invoked whenever the route is focused.
* console.log('Hello, I'm focused!');
*
* // Return function is invoked whenever the route gets out of focus.
* return () => {
* console.log('This route is now unfocused.');
* };
* }, []);
* );
*
* return </>;
* }
*```
*
* @param effect Memoized callback containing the effect, should optionally return a cleanup function.
* @param do_not_pass_a_second_prop
*/
function useFocusEffect(effect, do_not_pass_a_second_prop) {
const navigation = (0, useLoadedNavigation_1.useOptionalNavigation)();
if (do_not_pass_a_second_prop !== undefined) {
const message = "You passed a second argument to 'useFocusEffect', but it only accepts one argument. " +
"If you want to pass a dependency array, you can use 'React.useCallback':\n\n" +
'useFocusEffect(\n' +
' React.useCallback(() => {\n' +
' // Your code here\n' +
' }, [depA, depB])\n' +
');\n\n' +
'See usage guide: https://reactnavigation.org/docs/use-focus-effect';
console.error(message);
}
React.useEffect(() => {
if (!navigation) {
return;
}
let isFocused = false;
let cleanup;
const callback = () => {
const destroy = effect();
if (destroy === undefined || typeof destroy === 'function') {
return destroy;
}
if (process.env.NODE_ENV !== 'production') {
let message = 'An effect function must not return anything besides a function, which is used for clean-up.';
if (destroy === null) {
message +=
" You returned 'null'. If your effect does not require clean-up, return 'undefined' (or nothing).";
}
else if (typeof destroy.then === 'function') {
message +=
"\n\nIt looks like you wrote 'useFocusEffect(async () => ...)' or returned a Promise. " +
'Instead, write the async function inside your effect ' +
'and call it immediately:\n\n' +
'useFocusEffect(\n' +
' React.useCallback(() => {\n' +
' async function fetchData() {\n' +
' // You can await here\n' +
' const response = await MyAPI.getData(someId);\n' +
' // ...\n' +
' }\n\n' +
' fetchData();\n' +
' }, [someId])\n' +
');\n\n' +
'See usage guide: https://reactnavigation.org/docs/use-focus-effect';
}
else {
message += ` You returned '${JSON.stringify(destroy)}'.`;
}
console.error(message);
}
};
// We need to run the effect on initial render/dep changes if the screen is focused
if (navigation.isFocused()) {
cleanup = callback();
isFocused = true;
}
const unsubscribeFocus = navigation.addListener('focus', () => {
// If callback was already called for focus, avoid calling it again
// The focus event may also fire on initial render, so we guard against running the effect twice
if (isFocused) {
return;
}
if (cleanup !== undefined) {
cleanup();
}
cleanup = callback();
isFocused = true;
});
const unsubscribeBlur = navigation.addListener('blur', () => {
if (cleanup !== undefined) {
cleanup();
}
cleanup = undefined;
isFocused = false;
});
return () => {
if (cleanup !== undefined) {
cleanup();
}
unsubscribeFocus();
unsubscribeBlur();
};
}, [effect, navigation]);
}
exports.useFocusEffect = useFocusEffect;
//# sourceMappingURL=useFocusEffect.js.map