Typescript cryptic message when declaring function for one of my actions

I am using React, TypeScript and Redux. I seem to have an issue with using an interface for one of my actions. The cryptic message I am getting is:

Duplicate identifier 'number'.ts(2300)
Binding element 'number' implicitly has an 'any' type.ts(7031)

And in VS code the number both on limit: and skip: is underlined with a red error squiggly line.

Snipped of my code:

interface TabNavUnitsProps {
  unitsToRegister: number,
  unit: { status: string, unitsRegisterCount: number },
  fetchRegisterAll: ({ limit: number, skip: number }) => Promise<void>
}

export class TabNavUnits extends React.Component<TabNavUnitsProps> {

  state = {
    unitsRegisterCount: 0
  }

  componentDidMount() {
    this.props.fetchRegisterAll({ limit: 1, skip: 1 })
    .then(() => {
      if(this.props.unit.status === fetchStates.success) {
        this.setState({ unitsRegisterCount: this.props.unit.unitsRegisterCount })
      }
    })
  }

I admit part of the problem is I am new to this so thank you to anyone who is willing to help or point me in the right direction.

>Solution :

Just declare fetchRegisterAll correctly:

  fetchRegisterAll: (options: { limit:number , skip: number }) => Promise<void>