Error map
[Vue warn]: Avoid adding reactive properties to a Vue instance or its root $data at runtime Vue 2: [Vue warn]: Avoid adding reactive properties to a Vue instance or its root $data at runtime - declare it upfront in the data option
Vue · layer 1, On your device
Centre: this error. First ring: errors it is linked with (7). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (7)
Vue: [Vue warn]: Property "x" was accessed during render but is not defined on instance
The template references a variable/function that the component doesn’t expose.
Vue: [Vue warn]: Avoid mutating a prop directly since the value will be overwritten whenever the parent component re-renders
A child component assigned to a prop. Props flow one way — the parent owns the value.
Vue: [Vue warn]: Maximum recursive updates exceeded in component <Foo>. This means you have a reactive effect that is mutating its own dependencies and thus recursively triggering itself
A watcher/computed/render effect keeps changing the state it depends on, creating an infinite update loop.
Vue: [Vue warn]: Set operation on key "name" failed: target is readonly.
You mutated a readonly reactive object (props, `readonly()`, `shallowReadonly`, or a frozen/store state).
Vue: [Vue warn]: Write operation failed: computed value is readonly
You assigned to a `computed` that has no setter.
Vue 2: [Vue warn]: Error in v-on handler: "TypeError: Cannot read property 'x' of undefined"
An exception was thrown inside a Vue 2 event handler or lifecycle hook, logged with context.
Vue: [Vue warn]: Slot "default" invoked outside of the render function: this will not track dependencies used in the slot
A slot function was called outside render (in `setup`, a computed or watcher), so reactivity isn't tracked.
Two steps away (16)
ReferenceError: x is not defined
Code refers to a variable or function name that doesn’t exist in the current scope.
django.template.exceptions.TemplateDoesNotExist: app/page.html
Django searched all template directories and couldn’t find that template.
Angular: NG8002: Can't bind to 'ngModel' since it isn't a known property of 'input'
The template uses a property binding that no imported directive provides — for ngModel, FormsModule isn’t imported.
Warning: Received `true` for a non-boolean attribute `x`.
A boolean was passed to a DOM attribute that expects a string, or a custom prop leaked through to a DOM element.
Warning: `key` is not a prop. Trying to access it will result in `undefined` being returned.
A component tried to read props.key, which React reserves and never passes down.
Vue: [Vue warn]: Failed to resolve component: x
The template uses a component tag that isn’t registered or imported where it’s used.
Vue: [Vue warn]: Unhandled error during execution of mounted hook / TypeError: Cannot read properties of undefined (reading 'x')
An exception was thrown inside a lifecycle hook, watcher, event handler or render, and Vue logs it with the context.
Vue: [Vue warn]: Vue received a Component that was made a reactive object — mark it with `markRaw` or use `shallowRef`
A component definition was stored in a `ref`/`reactive`, making Vue proxy it unnecessarily.
Next.js: Error: Failed prop type: The prop `href` expects a `string` or `object` in `<Link>`, but got `undefined` instead
`` received `undefined` (or another invalid value), so Next.js can't build the link.
Vue: [Vue warn]: Invalid prop: type check failed for prop "count". Expected Number with value 5, got String with value "5"
A prop received a value of the wrong type.
Vue: [Vue warn]: Missing required prop: "title"
A component marked a prop as `required` but the parent didn't pass it.
Vue: [@vue/compiler-sfc] v-model cannot be used on a prop, because local prop bindings are not writable
A template uses `v-model` on a prop (or a `v-for` alias), which can't be assigned.
Nuxt: 404 Page not found: /blog/my-post / [Vue Router warn]: No match found for location with path
Nuxt's file-based router has no page matching the URL (wrong file/folder names or missing param syntax).
Nuxt: [vite] Internal server error: Failed to resolve import "~/components/Foo.vue" from "pages/index.vue". Does the file exist?
Vite couldn't resolve an alias import — the file doesn't exist at that path or the alias isn't defined.
Vue: [Vue warn]: onMounted is called when there is no active component instance to be associated with
A lifecycle hook was registered outside `setup()` (or after an `await`).
Vue: [Vue warn]: Component is missing template or render function.
A component object has neither `template` nor `render`, or an SFC import resolved wrongly.
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Popular: 500403400ORA-009331064Critical errorFileNotFoundException assemblyTypeError