// Given:
interface Foo {
    simpleMember: number;
    optionalMember?: string;
    objectMember: X; // Where X is a inline object type, interface, or other object-like type 
}

// This:
var foo: partial Foo;
// Is equivalent to:
var foo: {simpleMember?: number, optionalMember?: string, objectMember?: X};

// And this:
var bar: deepPartial Foo;
// Is equivalent to:
var foo: {simpleMember?: number, optionalMember?: string, objectMember?: deepPartial X};