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

Beginne mit dem verlinkten TypeScript Playground und reproduziere den Kontrast zwischen den drei Beispielen, insbesondere die kontextuelle Typisierung der dynamischen Template-Literal-Eigenschaft in Example 1. Vergleiche den inferierten Typ von e mit den Fällen mit statischem Schlüssel und generischer Funktion; abgeschlossen ist es, wenn Example 1 e als den gezeigten Parametertyp { name: string } inferiert.