打字稿递归更改属性类型

Question

How to change property type recursively, im only able to do it in single dimension, judging from utility-types it seem to possible to achive that, i have tried coupe of times but can't get it right

type Convert<V, O extends object> = {
    [Key in keyof O] : V
}

// single
{
    let original = {
        data1 : 1,
        data2 : 1,

    };

    let converted : Convert<string, typeof original> = {
        data1: 'a',
        data2: 'a',
    };
}

// recursive
{
    let original = {
        data1 : 1,
        data2 : 1,
        data3 : {
            data1 : 1,
            data2 : 1,
        }
    };

    let converted : Convert<string, typeof original> = {
        data1: 'a',
        data2: 'a',
        data3 : {
            data1 : 'a',
            data2 : 'a',
        }
    };
}

Answer 1

I'm pretty sure you want a recursive conditional type where you only recurse down into properties which are themselves objects:

type Convert<V, O extends object> = {
    [K in keyof O]: O[K] extends object ? Convert<V, O[K]> : V
}

This will cause your example code to succeed, but there may be edge cases surrounding non-primitive properties you don't want to recurse into (eg, arrays?), so you should test it thoroughly.

Hope that helps; good luck!

Playground link to code