type inference issue with dynamic template literals

🔎 Search Terms

"template literals and type inference", "type inference with dynamic template literals"

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about it

⏯ Playground Link

https://www.typescriptlang.org/play/?ts=5.4.5#code/C4TwDgpgBAgmCWUC8UDeAoKUDaBrCIAXFAAYAWEANpQPYB0AJKgM7ABO8AdgOYC+JAXWIAKACYBDYOOKooncQFsIxVhx5ReASmQA+KADca8Uel7p0lCMCgBXZhDYBJUSvZduyKAHJRIeQvgAYyhVdy9zAHoIqABRAA9FMEsARmIAERoIZk4vawB3GjZcOihQSCgAM0LSCBIoQPEc6wAjaC4KhzYIE0CaTlZSrOBU2ARPDCxscipaRlQ7B2d+IShoJD0JrHq+5hpLOlpuYQg6fwhNTA0AGlNI6PjEywAmYgB1QtxmdF7+62Ahl6jRAoTZTCjUeisSRBAD6oR4gmIaw2lywP12+0Ox1OinOl14NzM6CisQSCiSEAAzG8Pl90dY+p4ADwAaVWcX+nFEzCg+BANAqQJ0wkufOILJuWHEgWA8D6IgkUmIcHg2BZAm06wMRlEN01KKwJN2SighyCt3QfWE0whcwWTlE-Cuq10aEu6L2JyxJzOFy0QA

💻 Code

type Api = {
  [key: `hello.${string}`]: (data: { name: string }) => void
}

let userId: string = 'dynamic string'

// Example1: Doesn't work. type for `e` can't be inferred
const test1: Api = {
  [`hello.${userId}`]: e => {
    console.log(e.name)
  },
}

// Example2: Works
const test2: Api = {
  [`hello.static_string`]: e => {
    console.log(e.name)
  },
}

// Example3: Works
const on = <K extends keyof Api>(
  key: K,
  action: (data: Api[K]) => void,
) => {
  // some logic
}

on(`hello.${userId}`, e => {
  console.log(e.name)
})

🙁 Actual behavior

Example 1 doesn't work, while Example 2 and Example 3 works properly. The type for e can't be inferred

🙂 Expected behavior

To infer type of e in the Example 1.

Additional information about the issue

No response

リンクされた TypeScript Playground から始め、3 つの例の違いを再現します。特に、Example 1 における動的な template-literal プロパティの文脈的型付けを確認してください。e の推論された型を、静的キーの場合およびジェネリック関数の場合と比較します。Example 1 で e が示されている { name: string } パラメーター型として推論されれば完了です。