Lets say I want to define a function that accepts one argument that must be an object which keys are strings and values can be for example number | string like it done in the bottom example.
const fn = (param: Record<string, string | number>) => {
console.log(param);
};
const p = {
id: 1,
name: 'John'
};
fn(p);
the above example will work just fine, but when I want to give an explicit type to variable p with using typescript's type as in the bottom example, everything working just fine again.
const fn = (param: Record<string, string | number>) => {
console.log(param);
};
type User = {
id: number;
name: string;
}
const p: User = {
id: 1,
name: 'John'
};
fn(p);
But when defining type with the typescript interface as in the example below I'm getting an error saying
TS2345: Argument of type 'User' is not assignable to parameter of type 'Record<string, string | number>'.
Index signature for type 'string' is missing in type 'User'.
const fn = (param: Record<string, string | number>) => {
console.log(param);
};
interface User {
id: number;
name: string;
}
const p: User = {
id: 1,
name: 'John'
};
fn(p);
So what is the reason for such a behavior?
How can I define type for function argument to be an object which keys should be string and values can be union type for example string | number and will work with both types and interfaces?
