Some advanced partial object type definitions for TypeScript

advanced-object-types.ts

// tslint:disable:align ban-types
export type DeepPartial<T> =
	T extends Array<infer U> ? DeepPartialArray<U> :
	T extends ReadonlyArray<infer V> ? DeepPartialReadonlyArray<V> :
	T extends object ? DeepPartialObject<T> :
	T;

export type DeepPartialNoMethods<T> =
	T extends Array<infer U> ? DeepPartialArrayNoMethods<U> :
	T extends ReadonlyArray<infer V> ? DeepPartialReadonlyArrayNoMethods<V> :
	T extends object ? DeepPartialObjectNoMethods<T> :
	T;

export interface DeepPartialArrayNoMethods<T> extends Array<DeepPartialNoMethods<T>> {}
export interface DeepPartialArray<T> extends Array<DeepPartial<T>> {}

export interface DeepPartialReadonlyArrayNoMethods<T> extends ReadonlyArray<DeepPartialNoMethods<T>> {}
export interface DeepPartialReadonlyArray<T> extends ReadonlyArray<DeepPartial<T>> {}

export type DeepPartialObject<T> = {
	[P in keyof T]?: DeepPartial<T[P]>;
};

export type NonFunctionPropertyNames<T> = NonNullable<{
	[P in keyof T]: T[P] extends Function ? never : P;
}[keyof T]>;

export type DeepPartialObjectNoMethods<T> = {
	[P in NonFunctionPropertyNames<T>]?: DeepPartialNoMethods<T[P]>;
};

export type DeepReadonly<T> =
	T extends Array<infer U> ? DeepReadonlyArray<U> :
	T extends Function ? T :
	T extends object ? DeepReadonlyObject<T> :
	T;

export interface DeepReadonlyArray<T> extends ReadonlyArray<DeepReadonly<T>> {}

export type DeepReadonlyObject<T> = {
	readonly [P in keyof T]: DeepReadonly<T[P]>;
};

export type ObjectInitializer<T> = DeepPartialNoMethods<DeepReadonly<T>>;