reactjstypescripttypestypescript-typings

Typescript input onchange event.target.value

In my react and typescript app, I use:

onChange={(e) => data.motto = (e.target as any).value}

How do I correctly define the typings for the class, so I wouldn't have to hack my way around the type system with any?

export interface InputProps extends React.HTMLProps<Input> {
...

}

export class Input extends React.Component<InputProps, {}> {
}

If I put target: { value: string }; I get :

ERROR in [default] /react-onsenui.d.ts:87:18
Interface 'InputProps' incorrectly extends interface 'HTMLProps<Input>'.
  Types of property 'target' are incompatible.
    Type '{ value: string; }' is not assignable to type 'string'.
Solution

  • Generally event handlers should use e.currentTarget.value, e.g.:

    const onChange = (e: React.FormEvent<HTMLInputElement>) => {
  const newValue = e.currentTarget.value;
}

    You can read why it so here (Revert "Make SyntheticEvent.target generic, not SyntheticEvent.currentTarget.").

    UPD: As mentioned by @roger-gusmao ChangeEvent more suitable for typing form events.

    const onChange = (e: React.ChangeEvent<HTMLInputElement>) => {
  const newValue = e.target.value;
}