Choo first app

index.js

const extend = require("xtend");
const choo = require("choo");
const html = require("choo/html");
const app = choo();

app.use({
  state: {
    todos: []
  },
  reducers: {
    receiveTodos: (state, data) => {
      return { todos: data };
    },
    receiveNewTodo: (state, data) => {
      const newTodos = state.todos.slice();
      newTodos.push(data);
      return { todos: newTodos };
    },
    replaceTodo: (state, data) => {
      const newTodos = state.todos.slice();
      newTodos[data.index] = data.todo;
      return { todos: newTodos };
    }
  },
  effects: {
    getTodos: (state, data, send, done) => {
      store.getAll("todos", todos => {
        send("receiveTodos", todos, done);
      });
    },
    addTodo: (state, data, send, done) => {
      const todo = extend(data, {
        completed: false
      });

      store.add("todos", todo, () => {
        send("receiveNewTodo", todo, done);
      });
    },
    updateTodo: (state, data, send, done) => {
      const oldTodo = state.todos[data.index];
      const newTodo = extend(oldTodo, data.updates);

      store.replace("todos", data.index, newTodo, () => {
        send("replaceTodo", { index: data.index, todo: newTodo }, done);
      });
    }
  }
});

const view = (state, prev, send) => {
  return html`
    <div onload=${() => send("getTodos")}>
      <form onsubmit=${onSubmit}>
        <input type="text" placeholder="New item" id="title">
      </form>
      <ul>
        ${state.todos.map(
          (todo, index) => html`
          <li>
            <input type="checkbox" ${
              todo.completed ? "checked" : ""
            } onchange=${e => {
            const updates = { completed: e.target.checked };
            send("updateTodo", { index: index, updates: updates });
          }} />
            ${todo.title}
          </li>`
        )}
      </ul>
    </div>`;

  function onSubmit(e) {
    const input = e.target.children[0];
    send("addTodo", { title: input.value });
    input.value = "";
    e.preventDefault();
  }
};

app.route([["/", view]]);

const tree = app.start();
document.body.appendChild(tree);

// localStorage wrapper
const store = {
  getAll: (storeName, cb) => {
    try {
      cb(JSON.parse(window.localStorage[storeName]));
    } catch (e) {
      cb([]);
    }
  },
  add: (storeName, item, cb) => {
    store.getAll(storeName, items => {
      items.push(item);
      window.localStorage[storeName] = JSON.stringify(items);
      cb();
    });
  },
  replace: (storeName, index, item, cb) => {
    store.getAll(storeName, items => {
      items[index] = item;
      window.localStorage[storeName] = JSON.stringify(items);
      cb();
    });
  }
};

package.json

{
  "name": "choo-t",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "start": "bankai start index.js",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "choo": "^6.7.0",
    "xtend": "^4.0.1"
  },
  "devDependencies": {
    "bankai": "^9.3.1"
  }
}

made those edits and now im getting this error

AssertionError: choo.use: cb should be type function

edit: I updated the index.js to just be a straight copy of the final sample code on the Choo first app page. made the use and route changes as well, also added xtend to the dependencies just like in the demo.