What are custom directives?
Interviewer Expectations for this Question
01
Core Competency
Assesses fundamental understanding of Vue.js conventions, runtime behavior, and memory/performance considerations.
02
Evaluation Criteria
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Comprehensive Model Answer
Verified Solution
Custom Directives are tiny commands that you can attach to DOM elements. They are prefixed with v- to let the
library know you're using a special bit of markup and to keep syntax consistent. They are typically useful if you
need low-level access to an HTML element to control a bit of behavior.
Let's create a custom focus directive to provide focus on specific form element during page load time,
// Register a global custom directive called `v-focus`
Vue.directive('focus', {
// When the bound element is inserted into the DOM...
inserted: function (el) {
// Focus the element
el.focus()
}
})
Now you can use v-focus directive on any element as below,
<input v-focus>
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- Start with a concise one-sentence summary: Deliver a direct, confident answer first before expanding into nuances.
- Demonstrate real-world trade-offs: Discuss where this approach excels and when you would avoid it in production systems.
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