Error map
[Vue warn]: Missing required prop Vue: [Vue warn]: Missing required prop: "title"
Vue · layer 1, On your device
Centre: this error. First ring: errors it is linked with (12). 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 (12)
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.
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.
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.
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.
TypeScript: error TS2741: Property 'email' is missing in type '{ name: string; }' but required in type 'User'.
An object lacks one required property of the target type.
Vue: [Vue warn]: Extraneous non-props attributes (class) were passed to component but could not be automatically inherited because component renders fragment or text root nodes
Attributes (class, style, listeners) passed to a component can't be applied because the component has multiple root nodes.
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).
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]: injection "theme" not found.
`inject("theme")` ran but no ancestor provided it.
TypeScript: error TS7031: Binding element 'name' implicitly has an 'any' type.
A destructured parameter has no type, so its elements default to `any`.
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]: Component emitted event "update" but it is neither declared in the emits option nor as an "onUpdate" prop
A component calls `emit("update")` without declaring it in `emits`.
Two steps away (32)
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: Each child in a list should have a unique "key" prop
When rendering a list with `.map()`, each element needs a stable, unique `key` so React can track items between renders.
Warning: A component is changing an uncontrolled input to be controlled
An input’s `value` started as `undefined` (uncontrolled) and later became a defined value (controlled), or vice versa.
IndexError: list index out of range
Code accessed a list position that doesn’t exist.
Error: Objects are not valid as a React child
You tried to render a plain object (or a Promise/Date) directly in JSX; React can only render strings, numbers, elements and arra…
Error: Nothing was returned from render. This usually means a return statement is missing.
A component returned undefined (React 17 and earlier) — usually a missing return or a return followed by a line break.
Adjacent JSX elements must be wrapped in an enclosing tag. Did you want a JSX fragment <>...</>?
A component returns two sibling JSX elements without a single parent.
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]: Duplicate keys found during update: "5", possible duplicate or missing keys
Items in a `v-for` list share the same `:key`, which breaks Vue's diffing.
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.
TS2339: Property 'x' does not exist on type 'Y'.
TypeScript’s type for the object doesn’t include that property.
TypeScript: error TS2551: Property 'lenght' does not exist on type 'string'. Did you mean 'length'?
A property name is misspelled (TypeScript suggests the closest valid one).
TypeScript: error TS2353: Object literal may only specify known properties, and 'nmae' does not exist in type 'User'
An object literal has an extra (or misspelled) property not in the target type (excess property check).
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
Vite can't process `.vue` files because the Vue plugin isn't installed/enabled.
ESLint: Parsing error: Unexpected token < / Parsing error: '>' expected (vue-eslint-parser not configured)
ESLint can't parse `.vue` files because the Vue parser isn't configured.
Vue: [Vue warn]: <TransitionGroup> children must be keyed: <li>
Children of `` lack a unique `key`, so animations can't track items.
Vue: [Vue warn]: Write operation failed: computed value is readonly
You assigned to a `computed` that has no setter.
Vuex (strict mode): Error: [vuex] do not mutate vuex store state outside mutation handlers.
Store state was modified directly (in a component or action) while strict mode is on.
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
In Vue 2 you added a property to the root data (or instance) after creation, which can't be made reactive.
You're importing a component that needs useState. It only works in a Client Component but none of its parents are marked with "use client"
In the Next.js App Router, a component using hooks or browser APIs is rendered as a Server Component.
Next.js: FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory (during next build)
Node ran out of memory while building a large Next.js app (or on a small CI/Vercel runner).
Next.js: Error occurred prerendering page "/blog" TypeError: fetch failed { cause: Error: connect ECONNREFUSED 127.0.0.1:3000 }
During `next build` a page tried to fetch data from a server (often your own app or an API) that isn't running yet.
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 Router: [Vue warn]: injection "Symbol(router)" not found. / Cannot read properties of undefined (reading 'push')
`useRouter()`/`useRoute()` ran in a component tree where the router plugin isn't installed.
Vue: [Vue warn]: Failed to locate Teleport target with selector "#modal". Note the target element must exist before the component is mounted
`` can't find its target element when mounting.
TS7006: Parameter 'x' implicitly has an 'any' type
A function parameter has no type annotation and TypeScript can’t infer one, which noImplicitAny (part of strict) forbids.
TypeScript: error TS7005: Variable 'x' implicitly has an 'any[]' type. / TS7034: Variable implicitly has type 'any' in some locations
With `noImplicitAny`, a variable's type can't be inferred and defaults to `any`.
TypeScript: error TS7053: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type '{ a: number; }'
You index an object with a general `string` key, but its type only knows specific keys.
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.
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.
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