Create a To-Do List App with React and JavaScript

React is an easy to use JavaScript framework that lets us create front end apps.

In this article, we’ll look at how to create a to-do list app with React and JavaScript.

Create the Project

We can create the React project with Create React App.

To install it, we run:

npx create-react-app todo-list

with NPM to create our React project.

We need the uuid to let us create unique IDs for our to-do items easily.

To add it, we run:

npm i uuidv4

Create the To-Do App

To create the to-do list app, we write:

import { useState } from "react";
import { v4 as uuidv4 } from "uuid";

export default function App() {
  const [todo, setTodo] = useState("");
  const [todos, setTodos] = useState([]);

  const submit = (e) => {
    e.preventDefault();
    setTodos((todos) => [
      ...todos,
      {
        id: uuidv4(),
        todo
      }
    ]);
  };

  const deleteTodo = (index) => {
    setTodos((todos) => todos.filter((_, i) => i !== index));
  };

  return (
    <div className="App">
      <form onSubmit={submit}>
        <input value={todo} onChange={(e) => setTodo(e.target.value)} />
        <button type="submit">Add</button>
      </form>
      {todos.map((t, i) => {
        return (
          <div key={t.id}>
            {t.todo}
            <button onClick={() => deleteTodo(i)}>delete</button>
          </div>
        );
      })}
    </div>
  );
}

We have the todo state which is bound to the input box.

The todos state has an array of to-do items.

The submit method is where we add the to-do items to the todos array.

We call e.preventDefault() to stop server-side form submission.

Then we call setTodos with a callback to get the todos and return an array with the original todos items.

After that, we append the new item to it.

It has an id created from the uuidv4 function.

todo has the to-do item text.

The deleteTodo function is called when we click the delete button.

In it, we call the setTodos method with a callback that takes the original todos array.

Then we return an array without the entry with the given index .

We filter that entry out with the filter method.

Then in the return statement, we have a form that has the input element with the value and onChange props to get the input value and set it with the onChange callback respectively.

onSubmit has the submit function as its value. submit is called when we click the Add button.

Below that, we have todos.map callback with a callback that returns a div with the t.todo rendered and a button to delete the item when we click it.

The key prop is set to t.id which is the unique ID.

This helps React identify the rendered array items properly.

Conclusion

We can create a to-do list app easily with React and JavaScript.