Lifecycle Hooks

This guide assumes that you have already read the Composition API Introduction and Reactivity Fundamentals. Read that first if you are new to Composition API.

Watch a free video about Lifecycle Hooks on Vue Mastery

You can access a component's lifecycle hook by prefixing the lifecycle hook with "on".

The following table contains how the lifecycle hooks are invoked inside of setup():

Options API	Hook inside setup
beforeCreate	Not needed*
created	Not needed*
beforeMount	onBeforeMount
mounted	onMounted
beforeUpdate	onBeforeUpdate
updated	onUpdated
beforeUnmount	onBeforeUnmount
unmounted	onUnmounted
errorCaptured	onErrorCaptured
renderTracked	onRenderTracked
renderTriggered	onRenderTriggered

TIP

Because setup is run around the beforeCreate and created lifecycle hooks, you do not need to explicitly define them. In other words, any code that would be written inside those hooks should be written directly in the setup function.

These functions accept a callback that will be executed when the hook is called by the component:

// MyBook.vue

export default {
  setup() {
    // mounted
    onMounted(() => {
      console.log('Component is mounted!')
    })
  }
}