Element implicitly has an 'any' type because the expression of type 'any' can't be used to index type '{ 1: number; 2: number; 3: number; }'

Question

The following code throws:

Element implicitly has an 'any' type because the expression of type 'any' can't be used to index type '{ 1: number; 2: number; 3: number; }'.

const obj = {
  1: 1,
  2: 2,
  3: 3,
}

fetch('http://example.com/foo.json')
  .then(response => response.json())
  //                        👇 throws
  .then(data => console.log(obj[data]))

Instead of listing all possible keys:

const obj = {
  1: 1,
  2: 2,
  3: 3,
}

fetch('http://example.com/foo.json')
  .then(response => response.json())
  //                                 👇 list all possible keys
  .then(data => console.log(obj[data as 1 | 2 | 3]))

Is there a better way for fixing this error?

Answer 1

One-liner:

const obj = {
  1: 1,
  2: 2,
  3: 3,
}

fetch('http://example.com/foo.json')
  .then(response => response.json())
  //                                 👇 one-liner
  .then(data => console.log(obj[data as keyof typeof obj]))