Update TypeScript objects given a string path and a value.

patcher.ts

const separator = ".";

const updateRecursively = <T extends Record<string, any>>(
    data: T,
    keys: string[],
    value: unknown
): T => {
    const [key] = keys;

    if (keys.length === 1)
        return {
            ...data,
            [key]: value,
        };

    return {
        ...data,
        [key]: updateRecursively(data?.[key] || {}, keys.slice(1), value),
    };
};

const updateObject = <T extends Record<string, any>>(
    data: T,
    path: string,
    value: unknown
): T => updateRecursively(data, path.split(separator), value);

const example1 = {};
console.log("Simple usage:", updateObject(example1, "b.c.d", 5));

const example2 = { b: { e: 8 } };
console.log("Keep the initial data: ", updateObject(example2, "b.c.d", 5));

const example3 = { b: { e: 8, c: 2 } };
console.log("Override data: ", updateObject(example3, "b.c.d", 5));

const example4 = { b: { e: 8, c: 2 } };
console.log("Complex value: ", updateObject(example4, "b.c.d", { f: 12 }));