Trigger and track for manual reactivity in Vue - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does trigger() do in Vue's manual reactivity?

trigger() tells Vue to re-run any effects that depend on a reactive value. It manually signals that the value changed.

beginner

What is the purpose of track() in Vue's manual reactivity system?

track() records which reactive effects depend on a value, so Vue knows what to update when that value changes.

intermediate

Why would you use manual reactivity with track() and trigger() instead of automatic reactivity?

Manual reactivity gives you control to decide exactly when to track dependencies and when to update, useful for custom reactive logic or performance tuning.

intermediate

In Vue, what happens if you call trigger() without calling track() first?

No reactive effects will run because Vue doesn't know which effects depend on the value without track().

beginner

How do track() and trigger() relate to real-life situations?

Think of track() as writing down who needs to be notified about a change, and trigger() as sending the notification when the change happens.

What does track() do in Vue's manual reactivity?

A It records dependencies for reactive updates

B It forces a component to re-render

C It resets reactive state

D It creates a new reactive variable

track() records which reactive effects depend on a value so Vue can update them later.

Which function manually signals Vue to update reactive effects?

A track()

B watch()

C trigger()

D ref()

trigger() tells Vue to re-run effects that depend on a reactive value.

What happens if you call trigger() without track()?

A Reactive state resets

B All effects run twice

C Vue throws an error

D No effects run

Without track(), Vue doesn't know which effects to update, so none run.

Why use manual reactivity with track() and trigger()?

A To control when dependencies are tracked and updated

B To create global variables

C To disable reactivity

D To automatically update all components

Manual reactivity lets you decide exactly when to track and trigger updates.

Which analogy best describes track() and trigger()?

A Writing a letter and mailing it

B Writing down who to notify and sending the notification

C Turning on and off a light switch

D Filling a bucket and emptying it

track() is like noting who to notify, trigger() is sending the notification.

Explain how track() and trigger() work together in Vue's manual reactivity system.

Think about how Vue knows what to update and when.

Describe a real-life example that helps you understand the roles of track() and trigger().

Imagine managing a group of friends to tell about a change.