Description
Bug Report
Previous discussion #37255 (comment)
Title is borrowed from @danielrentz #37255 (comment) I don't know if its accurate description of the problem.
🔎 Search Terms
None
🕗 Version & Regression Information
Any
⏯ Playground Link
💻 Code
import { FunctionComponent, useMemo } from 'react'
export interface ButtonProps {
size?: 'sm' | 'base' | 'lg'
}
export const Button: FunctionComponent<ButtonProps> = props => {
props.size ??= 'base'
const sizeClassNames = useMemo(() => {
return {
sm: 'px-3 py-2 text-sm',
base: 'px-4 py-2 text-sm',
lg: 'px-4 py-2 text-base'
}[props.size] // << Type 'undefined' cannot be used as an index type.(2538)
}, [props.size])
return (
<button
type="button"
className={sizeClassNames}
>
Button text
</button>
)
}🙁 Actual behavior
Type 'undefined' cannot be used as an index type.(2538)
🙂 Expected behavior
props.size should not be considered as undefined