Function makeNullable

src/GraphQL.ts:73–88

(
    builder: TypeBuilder,
    tref: TypeRef,
    name: string,
    fieldName: string | null,
    containingTypeName: string
)

}

function makeNullable(
    builder: TypeBuilder,
    tref: TypeRef,
    name: string,
    fieldName: string | null,
    containingTypeName: string
): TypeRef {
    const typeNames = makeTypeNames(name, fieldName, containingTypeName);
    const t = tref.deref();
    if (!(t instanceof UnionType)) {
        return builder.getUnionType(typeNames.names, false, OrderedSet([tref, builder.getPrimitiveType("null")]));
    }
    const [maybeNull, nonNulls] = removeNullFromUnion(t);
    if (maybeNull) return tref;
    return builder.getUnionType(typeNames, false, nonNulls.map(nn => nn.typeRef).add(builder.getPrimitiveType("null")));
}

function removeNull(builder: TypeBuilder, tref: TypeRef): TypeRef {
    const t = tref.deref();