In the below example I get the type error on obj[oid]

Element implicitly has an 'any' type because expression of type '2' can't be used to index type '{}'.

I imagine that I somehow have to specify that all the elements in the obj object are any, as I don't know the objects structure before hand?

import * as TOML from '@iarna/toml';
import * as fs from 'fs';

function readToml(filename: string): object {
  return TOML.parse(fs.readFileSync(filename, 'utf-8'));
}

const obj = readToml('./output/obj.toml');

const oid = 2;
const offerId = 1;

console.log(obj[oid].offers[offerId]);

CodePudding user response：

Yes. When you don't know the structure of an object at compile-time, you probably want to reach for the Record utility type. For instance, in this case you might make the return type of the readToml function Record<string, any>, which says "An object whose properties have string keys and any values."

function readToml(filename: string): Record<string, any> {
// −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−^^^^^^^^^^^^^^^^^^^
    return TOML.parse(fs.readFileSync(filename, 'utf-8'));
}

Playground link

If you don't even know for sure it'll be an object, you'd use any, or if you know it will be just one of several types, you'd use a union of those types. For example, if you knew that you'd get back either a Record<string, any> or a string (but not, say, a number or boolean), you could use the type Record<string, any> | string to express that at the type level. (That's not likely in this case, it's just meant as an example for other situations.)