I have to write mapStateToProps like below
function mapStateToProps(state, ownProps) {
return {
node: ownProps.info? state.TreeNodeReducer.tree[ownProps.info.path] : {}
};
}
combine reducer:
import { combineReducers } from 'redux';
import TreeNodeReducer from './TreeNodeReducer'
const rootReducer = combineReducers({
TreeNodeReducer
});
export default rootReducer;
reducers/TreeNodeReducer.js
import { OPEN_NODE, CLOSE_NODE, GET_NODES } from '../constants/NodeActionTypes';
const initialState = {
open: false,
info: {}
}
class NodeModel {
constructor(path, type, right) {
this.name = path;
this.path = path;
this.type = type;
this.right = right;
}
}
let lastId = 0;
function getFileList() {
var testNodes = []
for (var i=0; i< 3; i++) {
testNodes.push(new NodeModel(lastId,'d', i.toString()))
lastId++;
}
return testNodes
}
const getNodes = (state, action) => {
var { path } = action
var tree = state.tree ? state.tree : {}
tree[path] = getFileList(path)
return {
...state,
tree:tree
};
};
export default function (state = initialState, action) {
switch (action.type) {
case OPEN_NODE:
return { ...getNodes(state, action), open:true };
case GET_NODES:
return getNodes(state, action);
case CLOSE_NODE:
return {
...state,
open:false
};
default:
return state;
}
}
because state.TreeNodeReducer.tree is a global state, which hold all node info, I want to access it by state directly.State return by a reducer would wrap by the reducer's name, which is not convenient for simple project. Office doc don't provide the way.Any idea?
PS: I have to say I want to keep using combineReducers, I see some project not use it, directly pass reducer to store which can achieve my purpose but not good.
Achieving what you desire depends a bit on the state handled by the TreeNodeReducer.
If that reducer just handles the tree property, like this:
function treeNodeReducer(state = initialState, action) {
switch (action.type) {
case SOME_ACTION:
return Object.assign({}, state, { tree: action.tree, ... })
default:
return state
}
}
I'd say change the reducer to eliminate the tree property and merge it directly with the state, like this:
function treeNodeReducer(state = initialState, action) {
switch (action.type) {
case SOME_ACTION:
return Object.assign({}, state, action.tree)
default:
return state
}
}
This way we can access the tree object in mapStateToProps with state.treeNodeReducer.
But this is still not what we want. We want to rename treeNodeReducer to tree. There are two solutions for that:
Either:
import { combineReducers } from 'redux';
import TreeNodeReducer from './TreeNodeReducer'
const rootReducer = combineReducers({
tree: TreeNodeReducer
});
export default rootReducer;
Or:
import { combineReducers } from 'redux';
import tree from './TreeNodeReducer'
const rootReducer = combineReducers({
tree
});
export default rootReducer;
This way we can access the tree object in mapStateToProps with state.tree.
Related
I'm having this issue where my props are ending up looking like this (on console.log):
{
fetchRoles: f(),
roles:
roles: ["Admin", "Manager"],
}
As you can see, somewhere in my code I'm making a mistake that causes the roles prop to get nested into itself, which would force me into doing const { roles } = this.props.roles; in order to retrieve my data (which works BTW).
I've looked around for help but not many people seem to have run into this issue (I'm just getting started with redux).
Below you can see my files:
rolesReducer.js:
import { FETCH_ROLES } from "../actions/types";
const initialState = {
roles: [],
};
export default function (state = initialState, action) {
const { roles } = action;
switch (action.type) {
case FETCH_ROLES:
return {
...state, //also tried ...state.roles and same issue.
roles,
};
default:
return state;
}
}
rolesActions.js:
import { FETCH_ROLES } from "./types";
const roles = ["SuperAdmin"];
export function fetchRoles() {
return function (dispatch) {
dispatch({
type: FETCH_ROLES,
roles,
});
};
}
reducers/index.js (root reducer):
import { combineReducers } from "redux";
import rolesReducer from "./rolesReducer";
import roleMembersReducer from "./roleMembersReducer";
export default combineReducers({
roles: rolesReducer,
roleMembers: roleMembersReducer,
});
PermissionsManager.jsx:
import React, { Component } from "react";
import { connect } from "react-redux";
import { Container } from "react-bootstrap";
import { fetchRoles } from "../redux/actions/rolesActions";
import RoleContainer from "./RoleContainer";
class PermissionsManager extends Component {
componentDidMount() {
this.props.fetchRoles();
}
render() {
console.log(this.props);
const { roles } = this.props.roles;
return (
<Container>
{roles.map((role) => {
return <RoleContainer key={role} role={role} />;
})}
</Container>
);
}
}
const mapStateToProps = (state) => {
return {
roles: state.roles,
};
};
export default connect(mapStateToProps, { fetchRoles })(PermissionsManager);
Edit 1 - Adding reducer log:
As suggested, I logged the reducer, specifically state and action:
state:
{
roles: [],
}
action:
{
roles: ["Admin", "Manager"],
type: "FETCH_ROLES",
}
No duplication or abnormal structures I believe.
One way to shape the store like you're asking is to flatten roles in rolesReducer.js,
you can do so storing the received array directly in the partial state:
initialState would need to look like
const initialState = []
and in the switch statement
case FETCH_ROLES:
return roles
I am using the React Hooks implementation of React-Redux. Below is the flow of my code. For some reason any values that I pass in my dispatch(fuction(value)) is not detected in my reducer. I can't figure it out.
src/components/categories/selectCategory.tsx
import React from 'react';
import {useDispatch} from 'react-redux';
import {setCategory} from '../../store/actions';
const selectCategory = (name: string) => {
dispatch(setCategory(name)); // ex: name = 'algebra'
};
store/actions/index.ts
export const setCategory = (name) => ({
type: 'SET_CATEGORY',
name: name
});
store/reducers/index.ts
import {combineReducers} from 'redux';
import category from './category';
const app = combineReducers({
category
});
export default app;
store/reducers/category.ts
const initialState = {
name: 'calculus'
};
const category = (state = initialState, action) => {
switch (action.type) {
case 'SET_CATEGORY':
return {name: state.name}; // outputs 'calculus'
default:
return state;
}
};
export default category;
I'm sure there is some small detail I am missing.
My issue was fixed by returning the action.name property instead of state.name.
store/reducers/category.ts
const initialState = {
name: 'calculus'
};
const category = (state = initialState, action) => {
switch (action.type) {
case 'SET_CATEGORY':
return {name: action.name};
default:
return state;
}
};
export default category;
I wonder if React Native has a bug that needs fixing that gives the following error:
React Native: TypeError: undefined is not an object (evaluating
'_this.props.data.map')
I am pretty good at this and yet I cannot seem to resolve why I am getting this error when I put together this component:
import React, { Component } from "react";
import { View, Animated } from "react-native";
class Swipe extends Component {
renderCards() {
return this.props.data.map(item => {
return this.props.renderCard(item);
});
}
render() {
return <View>{this.renderCards()}</View>;
}
}
export default Swipe;
I have checked and double checked through various debugging practices that the problem is not with my action creator or reducer and after various refactors I got those working correctly.
I decided to do the above component from scratch whereas before I was reusing another component and yet I still get the above error.
I ask if it's a bug with RN because someone else posted a similar problem but they did not get the answer they needed.
It is not a scope issue with this because if I refactor it like so:
renderCards = () => {
return this.props.data.map(item => {
return this.props.renderCard(item);
});
};
It does absolutely nothing for me, same error message. The message saying is not an object is confusing too, it's an array and map() can only iterate through arrays, so not sure what not being an object has to do with it.
The above component is being called in this screen:
import React, { Component } from "react";
import { View, Text } from "react-native";
import { connect } from "react-redux";
import Swipe from "../components/Swipe";
class DeckScreen extends Component {
renderCard(job) {
return (
<Card title={job.title}>
<View style={styles.detailWrapper}>
<Text>{job.company}</Text>
<Text>{job.post_date}</Text>
</View>
<Text>
{job.description.replace(/<span>/g, "").replace(/<\/span>/g, "")}
</Text>
</Card>
);
}
render() {
return (
<View>
<Swipe data={this.props.jobs} renderCard={this.renderCard} />
</View>
);
}
}
const styles = {
detailWrapper: {
flexDirection: "row",
justifyContent: "space-around",
marginBottom: 10
}
};
function mapStateToProps({ jobs }) {
return { jobs: jobs.listing };
}
export default connect(mapStateToProps)(DeckScreen);
This is what the action creator looks like:
import axios from "axios";
// import { Location } from "expo";
import qs from "qs";
import { FETCH_JOBS, LIKE_JOB } from "./types";
// import locationify from "../tools/locationify";
const JOB_ROOT_URL = "https://authenticjobs.com/api/?";
const JOB_QUERY_PARAMS = {
api_key: "5634cc46389d0d872723b8c46fba672c",
method: "aj.jobs.search",
perpage: "10",
format: "json"
};
const buildJobsUrl = () => {
const query = qs.stringify({ ...JOB_QUERY_PARAMS });
return `${JOB_ROOT_URL}${query}`;
};
export const fetchJobs = (region, callback) => async dispatch => {
try {
const url = buildJobsUrl();
let { data } = await axios.get(url);
dispatch({ type: FETCH_JOBS, payload: data });
callback();
} catch (e) {
console.log(e);
}
};
export const likeJob = job => {
return {
payload: job,
type: LIKE_JOB
};
};
and reducer:
import { FETCH_JOBS } from "../actions/types";
const INITIAL_STATE = {
listing: []
};
export default function(state = INITIAL_STATE, action) {
switch (action.type) {
case FETCH_JOBS:
return action.payload;
default:
return state;
}
}
and the combineReducer is setup correctly as well:
import { combineReducers } from "redux";
import auth from "./auth_reducer";
import jobs from "./jobs_reducer";
import likedJobs from "./likes_reducer";
export default combineReducers({
auth,
jobs,
likedJobs
});
The listing: [] is based off the structure of the response I get back. When I console.log(data);, the actual data I care about is inside of listing property. So I set up the INITIAL_STATE to default listing to be an empty array with the intent to ensure I could map over the array and not worry about the case where I have not yet fetched the list of jobs. When I go to the API endpoint directly you can see it below:
I think the problem is simply that this.props.jobs is undefined. Your initial state is defined as { listing: [] }, however you mapStateToProps do { jobs: ... }.
Try changing initialState to { jobs: [] }, so that it always work on your first rendering.
I think your mapStateToProps should be:
mapStateToProps = (state) => {
return { jobs: listings.listing }
}
EDIT
Actually, it could be even better if you 'name' your state correctly in your reducer, like:
const INITIAL_STATE = { jobs: [] }
export default function(state = INITIAL_STATE, action) {
switch (action.type) {
case FETCH_JOBS:
const jobs = action.payload.listings.listing
return { ...state, jobs };
default:
return state;
}
}
Then in your mapStateToProps:
mapStateToProps = ({ jobs }) => {
return { jobs }
}
The issue is in your reducer. Please refer the below changes:
import { FETCH_JOBS } from "../actions/types";
const INITIAL_STATE = {
listing: []
};
export default function(state = INITIAL_STATE, action) {
switch (action.type) {
case FETCH_JOBS:
const { listings } = action.payload
return {...state, listing: listings.listing}
default:
return state;
}
}
Hope this will help.
function mapStateToProps({ jobs }) {
return { jobs: jobs.listing };
}
the above is making confusion for you try the below one
try to put
function mapStateToProps( state ) {
return { jobs: state.jobs.listing };
}
as you have defined your reducer as follow
export default combineReducers({
auth,
jobs,
likedJobs
});
jobs is your variable to access jobs reducer
I'm learning Redux and have come across an issue that I have not encountered before when using React without redux. I'm trying to display a piece of my state inside one of my components name loginStatus. The reducer I have setup this state with has an initial state but whenever I try and launch the application I get the console error:
Cannot read property 'loginStatus' of undefined
Here is my code:
Component
import React, {Component} from 'react';
import {connect} from 'react-redux';
import { bindActionCreators } from 'redux';
import * as authActions from './userAuthActions';
class App extends Component {
constructor(props) {
super(props);
}
render() {
if(typeof(this.props.userAuthReducer) !== 'undefined') {
test = this.props.userAuthReducer.loginStatus;
console.log(test)
} else {
console.log("it's undefined")
}
return (
<div className={"popup-logins " + this.props.userAuthReducer.loginStatus}>
</div>
);
}
}
const mapStateToProps = (state) => {
return {
userAuthReducer:state.userAuthReducer
};
};
const mapDispatchToProps = (dispatch) => {
return bindActionCreators(authActions,dispatch);
};
export default connect(mapStateToProps,mapDispatchToProps)(App);
userAuthActions.js
export const loginUser = () => {
return {
type:'loginUser',
loggedIn:true
}
}
export const toggleRegLog = () => {
return {
type:'toggleRegLog'
}
}
userAuthReducer
let initialState = {
loginStatus: "not-logged-in"
, toggleRegLog: 'login'
};
const userAuthReducer = (state = initialState, action) => {
switch (action.type) {
case 'loginUser':
let newState;
if (action.loggedIn) {
Object.assign({}, state, {
loginStatus: "logged-in"
})
}
else {
Object.assign({}, state, {
loginStatus: "not-logged-in"
})
}
return newState;
break;
default:
return state;
}
}
export default userAuthReducer;
combine reducers
import {combineReducers} from 'redux';
import userAuthReducer from './userAuthReducer';
function lastAction(state = null, action) {
return action;
}
export default combineReducers({
lastAction,userAuthReducer
});
What's strange is that I initially get a console.log of it's undefined" when I first start up the app and then immediately after I get the value "not-logged-in". I need to use this to hide/ show certain parts of my app if the user is logged in.
Normally if I use React without Redux I use this method all the time without any issues but can't understand what I might have done wrong here?
Thanks
You're not really assigning a value to newState in your reducer, so essentially you're returning undefined, which of course doesn't have a loginStatus property. Changing your reducer so to something like this will probably solve the problem:
let initialState = {
loginStatus: "not-logged-in"
, toggleRegLog: 'login'
};
const userAuthReducer = (state = initialState, action) => {
switch (action.type) {
case 'loginUser':
let newState;
if (action.loggedIn) {
newState = Object.assign({}, state, {
loginStatus: "logged-in"
})
}
else {
newState = Object.assign({}, state, {
loginStatus: "not-logged-in"
})
}
return newState;
break;
default:
return state;
}
}
export default userAuthReducer;
Object.assign returns a new object, applies the data from state and the last argument containing the loginStatus property and passes that to the newState variable, which gets returned at the end of the switch case.
Edit
This edit below makes it easier to reason about the logic in the reducer:
let initialState = {
loginStatus: "not-logged-in"
, toggleRegLog: 'login'
};
const userAuthReducer = (state = initialState, action) => {
switch (action.type) {
case 'loginUser':
if (action.loggedIn) {
return Object.assign(state, { loginStatus: "logged-in" })
}
return Object.assign(state, { loginStatus: "not-logged-in" })
default:
return state;
}
}
export default userAuthReducer;
I am new to redux, Is this correct way of doing redux in following code, please?
This is a reducer method when action called to execute currentTime.
import { combineReducers } from 'redux';
import { UPDATE_TIME } from './actions';
import { Map } from 'immutable';
const initialState = Map({update:false, currentTime: ""});
function currentTime(state = initialState, action) {
switch (action.type) {
case UPDATE_TIME:
return {...state, update: true, currentTime: action.time };
default:
return state;
}
}
const currentTimeReducer = combineReducers({
currentTime
});
export default currentTimeReducer
There are multiple ways to do it
You can set the value using set() function
case UPDATE_TIME:
state = state.set('update', true);
return state.set('currentTime', action.time);
or even
case UPDATE_TIME:
return state.set('update', true)
.set('currentTime', action.time);
However this is not feasible when you have multiple changes
The other option is merge()
case UPDATE_TIME:
return state.merge({update: true, currentTime: action.time})
However in case of a nested state update you would need to do a deepMerge. See the details of mergeDeep
We use immutable JS to create new instance on each small change in the existing object. Immutable JS MAP has a set method to set attribute and return new instance of the object.
Here you can find api doc for MAP
import { combineReducers } from 'redux';
import { UPDATE_TIME } from './actions';
import { Map } from 'immutable';
const initialState = Map({update:false, currentTime: ""});
function currentTime(state = initialState, action) {
switch (action.type) {
case UPDATE_TIME:
let newState = state;
newState = newState.set('update', true );
newState = newState.set('currentTime', action.time);
return newState;
default:
return state;
}
}
const currentTimeReducer = combineReducers({
currentTime
});
export default currentTimeReducer
Look best practices in this doc