Vue · Junior · Question 29 of 75

Why shouldn't a child mutate a prop?

✓Correct answer: Props follow one-way data flow: the parent owns the value, and Vue warns about mutations
2Props are frozen with Object.freeze, so mutation throws
3Mutation is allowed and updates the parent

Explanation

If the child needs to change the value, emit an event so the parent updates it, or copy the prop into local state if it's only an initial value.

Further reading

Vue: Props ↗

Test yourself

Take the Vue · Junior quiz: questions and options are shuffled, and you get a review of your mistakes at the end.