TypeScript with styled-components

Question

TypeScript newbie here. I have a below component using styled-components that I would like to convert to TypeScript.

import React from 'react'
import PropTypes from 'prop-types'
import styled from 'styled-components'


const propTypes = {
  name: PropTypes.string.isRequired // https://material.io/tools/icons/?style=baseline
}

const Icon = styled(({name, className, ...props}) => <i className={`material-icons ${className}`} {...props}>{name}</i>)`
  font-size: ${props => props.theme.sizeLarger};
`

Icon.propTypes = propTypes

export default Icon

I know I can replace my propTypes with an interface

interface Props {
  name: string
}

However, TypeScript complains that I leave className undeclared. The thing is, I would ideally like to use the interface as a sort of spec for props that a developer can provide, without having to declare props like className or theme which are injected by libraries like styled-components.

How do I properly convert this component to TypeScript?

Answer 1

import React from "react";
import styled from "styled-components";

interface Props {
  name: string;
  className?: string;
}

const NonStyledIcon: React.SFC<Props> = ({ name, className, ...props }) => (
  <i className={`material-icons ${className}`} {...props}>
    {name}
  </i>
);

const Icon = styled(NonStyledIcon)`
  font-size: ${props => props.theme.sizeLarger};
`;

export default Icon;

As per the styled-components TypeScript docs: when defining a component you will need to mark className as optional in your Props interface