How do you create reactive objects?

Peer-reviewed by HireXTech Technical Panel • Updated for 2025/2026 hiring • Editorial standards

Interviewer Expectations for this Question

Core Competency

Assesses fundamental understanding of Vue.js conventions, runtime behavior, and memory/performance considerations.

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

In version 3.0 you can create a reactive object with the reactive() API.

const reactiveState = reactive({
count: 0
 })

In version 2.6, you can create reactive objects with Vue.observable() global API.

const reactiveState = Vue.observable({
  count: 0
})

These observable objects can be used directly in computed properties and render functions.

const Demo = {
  render(h) {
    return h('button', {
      on: { click: () => { reactiveState.count++ }}
    }, `count is: ${state.count}`)
  }
}

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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.
Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
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