Develop Reference

hiding and showing array of images

So I have an array of images, which I would like to hide or show on a click of a button.
right now when I try to hide the image, it will hide the entire array.
import "./main.css";
import { FontAwesomeIcon } from "#fortawesome/react-fontawesome";
import React, { useEffect, useState } from "react";
import {
faCircleChevronLeft,
faCircleChevronRight,
faCircleXmark,
} from "#fortawesome/free-solid-svg-icons";
const Main = ({ galleryImages }) => {
const [slideNumber, setSlideNumber] = useState(0);
const [openModal, setOpenModal] = useState(false);
const [pics, setPics] = useState([]);
const [show, toggleShow] = useState(true);
// buttons next to name of diff charts (hide/show chart)
const handleOpenModal = (index) => {
setSlideNumber(index);
setOpenModal(true);
};
const removeImage = (id) => {
setPics((oldState) => oldState.filter((item) => item.id !== id));
};
// const hide = () => {
// setShow(false)
// }
const handleCloseModal = () => {
setOpenModal(false)
}
useEffect(()=> {
setPics(galleryImages)
},[]);
return (
<div>
<button onClick={() => toggleShow(!show)}>toggle: {show ? 'show' : 'hide'}</button>
{show &&
<div>
{pics.map((pic) => {
return (
<div style = {{marginBottom:'100px'}}>
{pic.id}
<img
src={pic.img}
width='500px'
height='500px'
/>
<button onClick ={() => removeImage(pic.id)}>Delete</button>
</div>
)
})}
</div>
I tried making a state component to try to hide and show the images, however it will hide the entire array instead of the individual image

i would add a show var to the galleryImages array and then set it so you get control of each image like this
import { useState } from "react";
import { v4 as uuidv4 } from "uuid";
import "./main.css";
import { FontAwesomeIcon } from "#fortawesome/react-fontawesome";
import React, { useEffect, useState } from "react";
import {
faCircleChevronLeft,
faCircleChevronRight,
faCircleXmark,
} from "#fortawesome/free-solid-svg-icons";
function Main({ galleryImages }) {
const [slideNumber, setSlideNumber] = useState(0);
const [openModal, setOpenModal] = useState(false);
const [pics, setPics] = useState([]);
// buttons next to name of diff charts (hide/show chart)
const toggleShow = ({ id, show }) => {
setPics((oldState) =>
oldState.map((item) => {
if (item.id !== id) return item;
return { ...item, show: !show };
})
);
};
const removeImage = (id) => {
setPics((oldState) => oldState.filter((item) => item.id !== id));
};
useEffect(() => {
setPics(
galleryImages.map((galleryImage) => {
return { ...galleryImage, show: true };
})
);
}, []);
return (
<div>
<div>
{pics.map((pic) => {
return (
<>
<button
onClick={() => toggleShow({ show: pic.show, id: pic.id })}
>
toggle: {pic.show ? "show" : "hide"}
</button>
{pic.show && (
<div style={{ marginBottom: "100px" }}>
{pic.id}
<img src={pic.img} width="500px" height="500px" />
<button onClick={() => removeImage(pic.id)}>Delete</button>
</div>
)}
</>
);
})}
</div>
</div>
);
}
export default Main;
`

If you would like the option to hide individual pics, to accomplish this you are correct in your state component approach.
First you can create a pic component that has its own state with a hide/show button:
export default function Pic({pic}) {
const [showPic, setShowPic] = useState(true);
const handleClick = () => {setShowPic(!showPic)}
return (
<div>
<div style={showPic ? {display : "block"} : {display : "none"}}>
<img
src={pic.img}
width='500px'
height='500px'
/>
</div>
<button onClick={handleClick}>{showPic ? 'Hide' : 'Show'}</button>
</div>
)
}
Next, you can import this component into your main file
import Pic from 'location/Pic.js';
and map each pic to a <Pic> component.
{pics.map((pic) => <Pic pic={pic} key={pic.id}/>)}
Now the images will be shown each with their own Hide/Show button that can toggle their display with the state contained within each <Pic/> component. This is good practice because toggling one image will not cause a re-render of the entire image gallery.

Filtering a todo list based on button clicked on React

I'm currently working on a to-do list app. Currently, I'm able to add, delete and edit the to-do list. I have a problem filtering my to-do list based on categories. The categories I have are all, active and completed. I'm stuck trying to filter the selected list based on the button clicked.
App.jsx:
import './App.css'
import Todo from './components/Todo';
import FilterButton from './components/FilterButton';
import Form from './components/form';
import { nanoid } from "nanoid";
function usePrevious(value) {
const ref = useRef();
useEffect(() => {
ref.current = value;
});
return ref.current;
}
const filterMap = {
All: () => true,
Active: (task) => !task.completed,
Completed: (task) => task.completed
};
const filterNames = Object.keys(filterMap);
function App(props) {
const [tasks, setTasks] = useState(props.tasks);
const [filter, setFilter] = useState('ALL');
function toggleTaskCompleted(id) {
const updatedTasks = tasks.map((task) => {
// if this task has the same ID as the edited task
if (id === task.id) {
// use object spread to make a new object
// whose `completed` prop has been inverted
return {...task, completed: !task.completed}
}
return task;
});
setTasks(updatedTasks);
}
function deleteTask(id) {
const remainingTasks = tasks.filter((task) => id !== task.id);
setTasks(remainingTasks);
}
function editTask(id, newName) {
const editedTaskList = tasks.map((task) => {
// if this task has the same ID as the edited task
if (id === task.id) {
return {...task, name: newName}
}
return task;
});
setTasks(editedTaskList);
}
const taskList =tasks
.filter((filterNames[filter]))
.map((task)=> (
<Todo
id={task.id}
name={task.name}
completed={task.completed}
key={task.id}
toggleTaskCompleted={toggleTaskCompleted}
deleteTask={deleteTask}
editTask={editTask}
/>
));
const filterList = filterNames.map((name) => (
<FilterButton
key={name}
name={name}
isPressed={name === filter}
setFilter={setFilter}
/>
));
function addTask(name) {
const newTask = { id: `todo-${nanoid()}`, name, completed: true };
setTasks([...tasks, newTask]);
}
const tasksNoun = taskList.length !== 1 ? 'tasks' : 'task';
const headingText = `${taskList.length} ${tasksNoun} remaining`;
const listHeadingRef = useRef(null);
const prevTaskLength = usePrevious(tasks.length);
useEffect(() => {
if (tasks.length - prevTaskLength === -1) {
listHeadingRef.current.focus();
}
}, [tasks.length, prevTaskLength]);
return (
<div className="todoapp stack-large">
<h1>TodoApp</h1>
<Form addTask={addTask} />
<div className="filters btn-group stack-exception">
{filterList}
</div>
<h2 id="list-heading" tabIndex="-1" ref={listHeadingRef}>
{headingText}
</h2>
<ul
role="list"
className="todo-list stack-large stack-exception"
aria-labelledby="list-heading"
>
{taskList}
</ul>
</div>
);
}
export default App;
FilterButton
''import React from "react";
function FilterButton(props) {
return (
<button
type="button"
className="btn toggle-btn"
aria-pressed={props.isPressed}
onClick={() => props.setFilter(props.name)}
>
<span className="visually-hidden">Show </span>
<span>{props.name}</span>
<span className="visually-hidden"> tasks</span>
</button>
);
}
export default FilterButton; ```

You're passing filterName that actually only contains the keys, not the method. Also, make sure you're getting tasks as an array from props.
Update your state as well to
const [tasks, setTasks] = useState(props.tasks || [] );
const taskList = useMemo(()=>tasks
.filter(filterMap[filter])
.map((task)=> (
<Todo
.....
/>
)),[tasks,filter]);
Also just wrap your taskList with useMemo so whenever tasks & filter change your taskList will be updated.

React js useState&useEffect array duplicates elements after a change

I am a beginner in react js programming. I'm trying to do the todo project, which is a classic project. When I delete or add an element from the list, the newly formed list appears on the screen by combining with the previous one, I will show it with a picture below. I did not understand the source of the eror so wanted to post it here to get some advices suggestions about why it is happening.Thank you.(I am getting and storing data in firebase firestore database)
Before Adding an element initial array state
After adding an element to the array.
I am using useState for array and using useEffect to get initial data
MainPage.js that contains form and the list components.
const MainPage = () => {
const [isLoading, setLoding] = useState(true);
const [array, setArray] = useState([]);
const sub = async (email) => {
var result = [];
await onSnapshot(doc(db, "users", email), (doc) => {
var data = doc.data().todos;
data.forEach((element) => {
Object.keys(element).map(() => {
result.push(element["title"]);
});
});
setArray(result);
setLoding(false);
});
};
useEffect(() => {
sub(auth.currentUser.email);
}, []);
const onAddToDo = (todoTitle) => {
setArray((prevAray) => {
return [...prevAray, todoTitle];
});
};
const onRemove = (title) => {
setArray((prevAray) => {
return [array.pop(array.indexOf(title))];
});
};
return (
<div>
{isLoading && <h1>Loading</h1>}
{!isLoading && (
<div>
<section>
<NavBar></NavBar>
<ToDoForm passData={onAddToDo} />
</section>
<section>
<CardList removeCards={onRemove} array={array} />
</section>
</div>
)}
</div>
);
};
export default MainPage;
Firebase.js that stores the firebase update methods
export const deleteItem = (title) => {
updateDoc(doc(db, "users", auth.currentUser.email), {
todos: arrayRemove({ title: title }),
});
};
export const addnewTodo = (title) => {
updateDoc(doc(db, "users", auth.currentUser.email), {
todos: arrayUnion({ title: title }),
});
};
TodoForm.js component
const ToDoForm = (props) => {
const [todoTitle, setTitle] = useState("");
const titleChangeHandler = (event) => {
setTitle(event.target.value);
};
const newTodoAdder = (event) => {
event.preventDefault();
addnewTodo(todoTitle);
props.passData(todoTitle);
};
return (
<div className="form_holder">
<div className="form_container">
<form onSubmit={newTodoAdder}>
<h3>Add Events</h3>
<label>Title</label>
<input
onChange={titleChangeHandler}
type="text"
placeholder="Title"
id="title"
></input>
<div className="holder">
<button type="sumbit">Add</button>
</div>
</form>
</div>
</div>
);
};
export default ToDoForm;
CardList.js component
const CardList = (props) => {
const array = props.array;
if (array.length === 0) {
return (
<div className="grid_container">
<h2>Found no todos</h2>
</div>
);
}
return (
<div className="grid_container">
{array.map((element, index) => {
return (
<Card
removeSelf={() => {
props.removeCards(element);
}}
key={index}
title={element}
/>
);
})}
</div>
);
};
export default CardList;
Card.js component
const Card = (props) => {
const handleRemove = (event) => {
event.preventDefault();
deleteItem(props.title);
props.removeSelf();
};
return (
<div className="card">
<h2 className="card__title">{props.title}</h2>
<button type="button" onClick={handleRemove}>
Delete
</button>
</div>
);
};
export default Card;
EDIT ;
Index.js file
import React from "react";
import ReactDOM from "react-dom/client";
import App from "./App";
import { BrowserRouter } from "react-router-dom";
const root = ReactDOM.createRoot(document.getElementById("root"));
root.render(
<BrowserRouter>
<App />
</BrowserRouter>
);

SOLUTION
I fixed the issue by changing the add and remove functions that were inside of MainPage.js file You can see the new versions bellow. Hope someday it will help somebody.
Use effect was called once all I had to do get the data again after a change...
New Remove and Add functions
const onAddToDo = (todoTitle) => {
console.log(todoTitle + " Added");
sub(auth.currentUser.email);
};
const onRemove = (title) => {
console.log(title + " Deleted");
sub(auth.currentUser.email);
};

How can I create an instance of an Object in React..?

I am very new to react and javascript, but I am trying to build a simple ToDo App. It wasn't complicated until I wanted to read data from a file and to display that data on the screen. The problem is that I don't know how to create a new Todo object to pass it as parameter for addTodo function.. Thaaank you all and hope you can help me!!
I will let the code here (please see the -loadFromFile- function, there is the problematic place:
import React, { useState } from 'react';
import TodoForm from './TodoForm';
import Todo from './Todo';
import data from './data/data.json'
function TodoList() {
const [todos, setTodos] = useState([]);
const loadFromFile = data.map( ( data) => {
const newTodo = addTodo(new Todo(data.id,data.text));
return ( {newTodo} )});
const addTodo = todo => {
if (!todo.text || /^\s*$/.test(todo.text)) {
return;
}
const newTodos = [todo, ...todos];
setTodos(newTodos);
console.log(...todos);
};
const updateTodo = (todoId, newValue) => {
if (!newValue.text || /^\s*$/.test(newValue.text)) {
return;
}
setTodos(prev => prev.map(item => (item.id === todoId ? newValue : item)));
};
const removeTodo = id => {
const removedArr = [...todos].filter(todo => todo.id !== id);
setTodos(removedArr);
};
const completeTodo = id => {
let updatedTodos = todos.map(todo => {
if (todo.id === id) {
todo.isComplete = !todo.isComplete;
}
return todo;
});
setTodos(updatedTodos);
};
return (
<>
<TodoForm onSubmit={addTodo} />
{loadFromFile}
<Todo
todos={todos}
completeTodo={completeTodo}
removeTodo={removeTodo}
updateTodo={updateTodo}
/>
</>
);
}
export default TodoList;
I want to create new instance of Todo object. I tried many times, many different forms, but still doesn't work. I have an id and a text from the data.json file. I want to create that instance of Todo object with these two values. But how?
import React, { useState } from 'react';
import TodoForm from './TodoForm';
import EditIcon from '#material-ui/icons/Edit';
import DeleteIcon from '#material-ui/icons/Delete';
const Todo = ({ todos, completeTodo, removeTodo, updateTodo }) => {
const [edit, setEdit] = useState({
id: null,
value: ''
});
const submitUpdate = value => {
updateTodo(edit.id, value);
setEdit({
id: null,
value: ''
});
};
if (edit.id) {
return <TodoForm edit={edit} onSubmit={submitUpdate} />;
}
return todos.map((todo, index) => (
<div
className={todo.isComplete ? 'todo-row complete' : 'todo-row'}
key={index}
>
<p> <div key={todo.id} onClick={() => completeTodo(todo.id)}>
{todo.text}
</div>
</p>
<div className='icons'>
<DeleteIcon fontSize="small"
onClick={() => removeTodo(todo.id)}
className='delete-icon'
/>
<EditIcon
onClick={() => setEdit({ id: todo.id, value: todo.text })}
className='edit-icon'
/>
</div>
</div>
));
};
export default Todo;
import React, { useState, useEffect, useRef } from 'react';
import { Fab, IconButton } from "#material-ui/core";
import AddIcon from '#material-ui/icons/Add';
function TodoForm(props) {
const [input, setInput] = useState(props.edit ? props.edit.value : '');
const inputRef = useRef(null);
useEffect(() => {
inputRef.current.focus();
});
const handleChange = e => {
setInput(e.target.value);
};
const handleSubmit = e => {
e.preventDefault();
props.onSubmit({
id: Math.floor(Math.random() * 10000),
text: input
});
setInput('');
};
return (
<form onSubmit={handleSubmit} className='todo-form'>
{props.edit ? (
<>
<textarea cols="10"
placeholder='Update item'
value={input}
onChange={handleChange}
name='text'
ref={inputRef}
className='todo-input edit'
/>
<button onClick={handleSubmit} className='todo-button edit'>
Save
</button>
</>
) : (
<>
<input
placeholder='Add item'
value={input}
onChange={handleChange}
name='text'
className='todo-input'
ref={inputRef}
/>
<Fab color="primary" aria-label="add">
< AddIcon onClick={handleSubmit} fontSize="small" />
</Fab>
</>
)}
</form>
);
}
export default TodoForm;

Issue
Ah, I see what you are getting at now, you are wanting to load some list of todos from an external file. The main issue I see in your code is that you are attempting to call/construct a Todo React component manually and this simply isn't how React works. You render data/state/props into JSX and pass this to React and React handles instantiating the components and computing the rendered DOM.
const loadFromFile = data.map((data) => {
const newTodo = addTodo(new Todo(data.id, data.text));
return ({newTodo});
});
Todo shouldn't be invoked directly, React handles this.
Solution
Since it appears the data is already an array of objects with the id and text properties, it conveniently matches what you store in state. You can simply pass data as the initial todos state value.
const [todos, setTodos] = useState(data);
If the data wasn't readily consumable you could create an initialization function to take the data and transform/map it to the object shape your code needs.
const initializeState = () => data.map(item => ({
id: item.itemId,
text: item.dataPayload,
}));
const [todos, setTodos]= useState(initializeState);
Running Example:
import data from "./data.json";
function TodoList() {
const [todos, setTodos] = useState(data); // <-- initial state
const addTodo = (text) => {
if (!text || /^\s*$/.test(text)) {
return;
}
setTodos((todos) => [todo, ...todos]);
};
const updateTodo = (id, newTodo) => {
if (!newTodo.text || /^\s*$/.test(newTodo.text)) {
return;
}
setTodos((todos) => todos.map((todo) => (todo.id === id ? newTodo : todo)));
};
const removeTodo = (id) => {
setTodos((todos) => todos.filter((todo) => todo.id !== id));
};
const completeTodo = (id) => {
setTodos((todos) =>
todos.map((todo) =>
todo.id === id
? {
...todo,
isComplete: !todo.isComplete
}
: todo
)
);
};
return (
<>
<TodoForm onSubmit={addTodo} />
<Todo
todos={todos}
completeTodo={completeTodo}
removeTodo={removeTodo}
updateTodo={updateTodo}
/>
</>
);
}

Filtering arrays in JS/React

So here I have search functionality. Everything works fine except when an Item has not been found in the array. I have tried something with objects.Keys but it is displaying it on the render not when the Book has not been found like it should. Should I use if statement or.
import React,{useState, useEffect, useRef, useContext}from 'react'
import {FaSearch} from 'react-icons/fa'
import {
Link, useHistory
} from "react-router-dom";
import { BookContext } from '../../context/books';
import SearchBooks from './SearchBooks';
const Search = () => {
const {data}= useContext(BookContext)
const [searchValue, setSearchValue] = React.useState('');
const history= useHistory()
const ref=useRef()
function filterBooks(book) {
console.log(book);
if (!searchValue.length ) return false;
return book.bookName?.toLowerCase().includes(searchValue.toLowerCase());
}
const handleSearch = (e) => {
if (ref.current && !ref.current.contains(e.target)) {
setSearchValue('')
}
};
useEffect(() => {
document.addEventListener('click', handleSearch);
return () => {
document.removeEventListener('click', handleSearch);
};
}, []);
return (
<div className='search__cont' ref={ref}>
{Object.keys(data).filter(filterBooks).length === 0 &&(
<div>
<h3>Book not found</h3>
</div>
)}
<SearchBooks searchValue={searchValue} setSearchValue={setSearchValue }/>
{Object.keys(data)
.map((key) => data[key])
.reduce((acc, curr) => acc.concat(curr), [])
.filter(filterBooks)
.map((book) => {
return (
<>
<div className='search__books'
onClick={() => {
history.push("/book/id", { book }); setSearchValue('')
}}
>
{" "}
{book.bookName}{" "}
</div>
</>
);
})}
</div>
)
}
export default Search

You're filtering the category names instead of the books (data is an object with category names as keys and books as values). You can use Object.values and Array.prototype.flat to get an array of all the books and then apply the filter.
const filteredBooks = Object.values(data).flat().filter(filterBooks)
const searchQueryPresent = searchValue.trim().length > 0
{
searchQueryPresent &&
(filteredBooks.length === 0 ? (
<div>No books found</div>
) : (
filteredBooks.map((book) => {
return <>{/* render books */}</>
})
))
}