As reference Remove blank attributes from an Object in Javascript, how to make it Typescript compatible?
JS function (nested objects | ES10):
function removeEmpty(obj) {
return Object.fromEntries(
Object.entries(obj)
.filter(([_, v]) => v != null)
.map(([k, v]) => [k, v === Object(v) ? removeEmpty(v) : v])
);
}
I've tried with Exclude<T, null> but it doesn't works with nested objects and I think it's not the correct utility to use.
Note that the returned type should remove null type(s) but keeps undefined.
Example/Expected behaviour:
type TestType = {
a?: {
b?: {
c: string;
} | null;
z?: {
x: string;
};
} | null;
};
const testObj: TestType = {
a: {
b: null,
z: { x: 'Hi' }
}
};
const resultObj = removeEmpty(testObj);
Where resultObj type is similar to:
type ResultTestTypeExample = {
a?: {
b?: {
c: string;
};
z?: {
x: string;
};
};
};
Does this work for you?
type ExpandRecursively<T> = T extends object
? T extends infer O ? { [K in keyof O]: ExpandRecursively<O[K]> } : never
: T;
type RemoveNull<T> = ExpandRecursively<{ [K in keyof T]: Exclude<RemoveNull<T[K]>, null> }>
Usage:
function removeEmpty<T>(obj: T): RemoveNull<T> {
return Object.fromEntries(
Object.entries(obj)
.filter(([_, v]) => v != null)
.map(([k, v]) => [k, v === Object(v) ? removeEmpty(v) : v])
) as RemoveNull<T>
}