midVue.js
What is 'Directive Composition' and how do custom directives handle arguments?
Updated May 4, 2026
Short answer
Custom directives allow low-level DOM access and can accept arguments via the : syntax.
Deep explanation
A directive's lifecycle hooks (mounted, updated, etc.) receive a binding object. This object contains the value (the expression result) and the arg (the string after the colon). This allows for highly configurable DOM behaviors.
Real-world example
Creating a directive that automatically focuses an input or integrates a 3rd party vanilla JS library like a datepicker.
Common mistakes
- Using directives for logic that could be handled with standard props and components.
Follow-up questions
- What are the lifecycle hooks for a custom directive in Vue 3?