How do you test mutations?
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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
Since mutations are just functions that completely rely on their arguments it will be easier to test. You need to
keep mutations inside your store.js file and should also export the mutations as a named export apart from default
export.
Let's take an example of increment mutations,
// mutations.js
export const mutations = {
increment: state => state.counter++
}
And test them using mocha and chai as below,
// mutations.spec.js
import { expect } from 'chai'
import { mutations } from './store'
// destructure assign `mutations`
const { increment } = mutations
describe('mutations', () => {
it('INCREMENT', () => {
// mock state
const state = { counter: 10 }
// apply mutation
increment(state)
// assert result
expect(state.counter).to.equal(11)
})
})
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