Troubleshooting¶

Look at the generated schema¶

If scrubbr is not returning the data you're expecting, the first place to look is at the internal schema definitions:

console.log(scrubbr.getSchema());

This is the JSON schema that was created from your TypeScript file.

Next look at the schema definition for the type you're trying to serialize to.

console.log(scrubbr.getSchemaFor('UserList'));

Verify that this returns a JSON schema object and that it contains the properties you want serialized.

Debug output¶

To enable debug logging:

import Scrubbr, { LogLevel } from 'scrubbr';

const scrubbr = new Scrubbr('./schema.ts', { logLevel: LogLevel.DEBUG });

Scrubbr can also nest the logs to make it easier to read:

const scrubbr = new Scrubbr('./schema.ts', {
  logLevel: LogLevel.DEBUG,
  logNesting: true, // or enter a string if you want to use a custom indention
});

Understanding the warning: "Guessing: Using type 'xyz', instead of 'abc' , because it has the fewest properties"¶

Guessing: Using type 'UserPublic', instead of 'UserRestricted', because it has the fewest properties at object path: 'user'.
(You can explicitly override this selection with the 'useType()' function in a custom serializer).

This warning happens when you have a type like this:

type Payload = {
  user: UserPublic | UserRestricted;
};

When Scrubbr gets to the user property, it doesn't know exactly how to choose between UserPublic and UserRestricted and so it makes a guess and chooses the type that defines the fewest properties (most restrictive). In the interest of performance, Scrubbr avoids doing deep introspection and type checking.

To avoid this warning, use a type alias return the useType function in a serializer:

type Payload = {
  user: User;
};
type User = UserPublic | UserRestricted;

scrubbr.addTypeSerializer('User', (data, state) => {
  if (/* type choosing logic here */) {
    return useType('UserRestricted');
  }
  return useType('UserPublic');
}