mobxjs / mobxjs/mobx-react-devtools
App works, but DevTools gives error "TypeError: this.todos is undefined"
Nobody has claimed this yet.
- Dominant language
- JavaScript
- Stars
- 1.2k
- Forks
- 45
- PR merge metrics
- No merged PRs in 30d
Description
The setup is simple. React with MobX and TypeScript along with MobX DevTools. The app is pretty much a copy paste of the 10 min todo introduction of MobX. The app works, but once I try to inspect the content of my store with DevTools I receive an error:

The code for the store is as follows:
export default class ObservableTodoStore {
@observable
todos: any[] = [];
@observable
pendingRequests: number = 0;
constructor() {
autorun(() => console.log(this.report));
}
@computed
get completedTodosCount() {
return this.todos.filter(
(todo: any) => todo.completed === true
).length;
}
@computed
get report() {
if (this.todos.length === 0) {
return '<none>';
}
return `Next todo: "${this.todos[0].task}". ` +
`Progress: ${this.completedTodosCount}/${this.todos.length}`;
}
@action
addTodo(task: any) {
this.todos.push({
task: task,
completed: false,
assignee: null
});
}
}
Contributor guide
No contributing guide indexed for this repository
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the ObservableTodoStore code in the issue and reproduce the failure while inspecting the store in MobX DevTools. Trace why DevTools reports that this.todos is undefined; done means the provided store can be inspected without the TypeError.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- react, typescript
- Domain
- frontend, tooling
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100