`script/no-side-effects-in-computed-properties`

Disallow side effects in Options API computed getters

Default severity: error
Presets: essential, happy-path, ecosystem, nuxt, opinionated
Automatic fix: None; review the suggested change
Applies to: JS/TS scripts in Vue SFCs; examples show the relevant Options API or script setup form
Options: No rule-specific options. Severity and preset selection are configurable.

Configuration (Vite+)

import { defineConfig } from "@vizejs/vite-plugin/vite-plus";

export default defineConfig({
  lint: {
    vize: {
      "preset": "incremental",
      "rules": {
        "script/no-side-effects-in-computed-properties": "error"
      }
    },
  },
});

vp run lint

Bad

doubled assigns to this.count, and reversed mutates this.items through reverse(). Both getters modify the state they are supposed to derive from.

<script lang="ts">
export default {
data() {
return { count: 0, items: [] }
},
computed: {
doubled() {
this.count = this.count * 2 // side effect: assigns to data
return this.count
},
reversed() {
return this.items.reverse() // side effect: mutates the array
}
}
}
</script>

Good

doubled returns the multiplication without assignment. reversed copies the array before reversing it, so the original component state is unchanged by the getter.

<script lang="ts">
export default {
data() {
return { count: 0, items: [] }
},
computed: {
doubled() {
return this.count * 2
},
reversed() {
return [...this.items].reverse() // operate on a copy
}
}
}
</script>

Good avoids this rule's finding under the configuration above; other rules may still report diagnostics.

Implementation · All rules