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Delete data from collection

Page 6 out of 10

Create the feature that will delete a todo task from the collection.

Clarice Bouwer

Software Engineering Team Lead and Director of Cloudsure

Sunday, 23 October 2022 · Estimated 2 minute read

Handler

This DELETE handler will delete an existing entry from your collection and handle certain error cases. his verb is encapsulated in the delete function of the getCollection function.

./netlify/functions/deleteTodo.js
Copy 
const { getCollection } = require('./astraClient');

exports.handler = async (event, context) => {
  try {
    const body = JSON.parse(event.body);
    const todos = await getCollection();
    try {
      const res = await todos.delete(body.id);
      return {
        statusCode: 200,
        body: JSON.stringify(res),
      };
    } catch (e) {
      return {
        statusCode: 400,
        body: JSON.stringify(e.message),
      };
    }
  } catch (error) {
    return {
      statusCode: 500,
      body: JSON.stringify(error.message),
    };
  }
};

API

./src/api.js
Copy 
const deleteTodo = async (id) => {
  const response = await fetch('/.netlify/functions/deleteTodo', {
    body: JSON.stringify({ id }),
    method: 'POST',
  });
  const deletedTodo = await respond(response);
  if (deletedTodo.deleted) {
    return id;
  }
  throw new Error(`Task ${id} was not deleted.`);
};

Don't forget to export the function.

./src/api.js
Copy 
const api = {
  getTodos,
  createTodo,
  deleteTodo,
};

export default api;

Delete tasks in the User Interface

You can just replace the existing file using the code below.

./src/App.js
Copy 
import React, { useEffect, useRef, useState } from 'react';
import api from './api';

const App = () => {
  const [todos, setTodos] = useState([]);
  const textbox = useRef();

  const setAndSortTodos = (items) => {
    setTodos(items.sort((x, y) => y.created - x.created));
  };

  useEffect(() => {
    const loadTodos = async () => {
      const data = await api.getTodos();
      setAndSortTodos(data);
    };
    loadTodos();
  }, []);

  const add = async () => {
    const task = textbox.current.value;
    if (task) {
      const result = await api.createTodo(task);
      if (result) {
        setAndSortTodos([...todos, result]);
        textbox.current.value = '';
      }
    }
  };

  // The second interaction function.
  // It will delete the todo task via the API
  // and update the todos array in the state
  // by setting and sorting a filtered copy
  // of the existing array.
  const remove = async (id) => {
    const result = await api.deleteTodo(id);
    if (result) {
      setAndSortTodos(todos.filter((t) => t.id !== id));
    }
  };

  return (
    <>
      <form onSubmit={(e) => e.preventDefault()}>
        <input ref={textbox} type="text" />
        <button onClick={add}>Add</button>
      </form>
      {todos && todos.length === 0 && <div>There is nothing to do.</div>}
      {todos &&
        todos.length > 0 &&
        todos.map((todo) => {
          return (
            <div key={todo.id}>
              {/* Add a button to remove the todo task. */}
              <button onClick={() => remove(todo.id)}>&times;</button>
              {todo.created} | {todo.id} | {todo.text}
            </div>
          );
        })}
    </>
  );
};

export default App;
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