[Vue warn]: The computed property "x" is already defined in data/props Vue Origin: On your device OSI layer 7 · Application Last updated 5 Nov 2026

Vue: [Vue warn]: The computed property "name" is already defined in data.

A name is used twice among props/data/computed/methods in the Options API.

Exact message you may see [Vue warn]: The computed property "name" is already defined in data.The computed property "x" is already defined as a prop.[Vue warn]: Method "x" has already been defined as a prop.[Vue warn]: The data property "x" is already declared as a prop. Use prop default value instead.computed property is already defined in data
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Seen on: Vue

Meaning

Rename one of them. The same applies to "Method "x" has already been defined as a prop", data vs props, or composition ref names shadowing template variables. Options API keys share one namespace on the component instance.

Common causes

  • Same name in data and computed
  • Method name equals a prop
  • Prop name equals a data key
  • Copy/paste leftovers
  • Mixins introducing the same name

⚡ Quick fix

  1. Rename the duplicate (fullName vs name)
  2. Remove the redundant data field
  3. Check mixins for collisions

Detailed fix by platform

Vue

  1. props: ["name"], computed: { displayName() { return this.name.toUpperCase() } }

How to diagnose

  1. Names — Duplicate?
  2. Mixins — Collision?
  3. Namespace — Unique?

🔧 Still not fixed?

Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:

Where this error sits

Origin: On your device. Errors that are often confused with or caused by this one (click to open):

[Vue warn]: Invalid prop: type check failed — Vue: [Vue warn]: Invalid prop: type check failed for prop "count". Expected Number with value 5, got String with value "5" (Vue)[Vue warn]: Invalid p…Avoid mutating a prop directly — Vue: [Vue warn]: Avoid mutating a prop directly since the value will be overwritten whenever the parent component re-renders (Vue)Avoid mutating a prop…ESLint Parsing error in .vue files — ESLint: Parsing error: Unexpected token < / Parsing error: '>' expected (vue-eslint-parser not configured) (Vue)ESLint Parsing error …Property was accessed during render but is not defined — Vue: [Vue warn]: Property "x" was accessed during render but is not defined on instance (Vue)Property was accessed…Vite: Failed to parse source / Unknown file extension ".vue" — Vite/Vue: [plugin:vite:import-analysis] Failed to parse source for import analysis — you may need to install appropriate plugins to handle the .vue file format (Vue)Vite: Failed to parse…vue-loader was used without the corresponding plugin — Webpack: Error: [vue-loader] vue-loader was used without the corresponding plugin. Make sure to include VueLoaderPlugin in your webpack config. (Vue)vue-loader was used w…vue/multi-word-component-names — ESLint: error Component name "Home" should always be multi-word vue/multi-word-component-names (Vue)vue/multi-word-compon…[Vue warn…

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