reduxjs/react-redux · error

Invalid value of type

Error message

Invalid value of type ${typeof arg} for ${name} argument when connecting component ${options.wrappedComponentName}.

What it means

connect's first three arguments (mapStateToProps, mapDispatchToProps, mergeProps) must each be a function, an object, or undefined/null. When a value of any other type is passed, react-redux returns this factory that immediately throws at connect time, naming the offending argument and the wrapped component.

Solutions

1. Check the argument in the named slot of the connect() call and ensure it is a function, an object of action creators, or undefined/null
2. Verify imports: a default/named import that resolves to the wrong module export is the most common cause
3. Pass connect options as the 4th argument: connect(mapState, mapDispatch, null, { forwardRef: true })

Example fix

// before
const C = connect(mapStateToProps, 'someString')(MyComponent)
// after
const C = connect(mapStateToProps, mapDispatchToProps)(MyComponent)

function isConnectArg(v) {
  return typeof v === 'function' || (v !== null && typeof v === 'object') || v == null;
}
if (!isConnectArg(mapStateToProps)) throw new TypeError('mapStateToProps must be a function, object, or undefined');

function isMapDispatch(v: unknown): v is Record<string, (...a: any[]) => any> | ((...a: any[]) => any) | undefined {
  return typeof v === 'function' || (v !== null && typeof v === 'object') || v === undefined;
}

try {
  const Connected = connect(mapState, mapDispatch)(Component)
} catch (e) {
  console.error('connect argument invalid:', e.message)
  throw e // connect errors are programmer errors; fail fast
}

When it happens

Trigger: Calling connect() with e.g. a boolean, number, or string as mapStateToProps/mapDispatchToProps/mergeProps — typically the result of a bad import (undefined vs. wrong value), a typo passing the wrong variable, or calling connect(validMapState, 'store') instead of passing options as the fourth argument.

Common situations: Circular imports leaving a factory as an unexpected value, copy-pasted connect calls where an options object was shifted into the mergeProps slot, or passing a plain non-object constant from misconfigured HOC helpers.

Related errors

• Unexpected value for
• You must pass a component to the function returned by…
• You must pass a valid React context consumer as…
• could not find react-redux context value; please ensure the…
• Could not find "store" in the context of

AI-assisted analysis of reduxjs/react-redux@16f1a91eb2 (2026-08-31). Data as JSON: /api/errors/0634cbecbe078f6d. Report an issue: GitHub.

Appendix: source

Thrown at src/connect/invalidArgFactory.ts:8

import type { Action, Dispatch } from 'redux'

export function createInvalidArgFactory(arg: unknown, name: string) {
  return (
    dispatch: Dispatch<Action<string>>,
    options: { readonly wrappedComponentName: string },
  ) => {
    throw new Error(
      `Invalid value of type ${typeof arg} for ${name} argument when connecting component ${
        options.wrappedComponentName
      }.`,
    )
  }
}

View on GitHub (pinned to 16f1a91eb2)