FixtureKit

FixtureKit is a specialized TypeScript mock data generator that converts TypeScript interface definitions into realistic, ready-to-use mock data. Targeted at developers building TypeScript applications, it serves as a productivity tool for generating test fixtures, prototype data, and sample records without manual creation. The core value lies in automatically deriving mock data from type structures, eliminating the repetitive task of writing mock objects and ensuring consistency between types and data. By simply defining an interface, developers can obtain fully populated mock objects with realistic field values, including standard identifier formats, email addresses, names, and timestamps. This streamlined approach accelerates development workflows in testing, demo building, and frontend development.

A common pain point in TypeScript development is the manual creation of realistic mock data that aligns with evolving type definitions. Developers often write repetitive mock objects, leading to errors and maintenance overhead. When interfaces change, mock data must be updated manually, risking inconsistencies. This becomes particularly problematic when using ORMs like Prisma, where mocks must exactly match model fields, including required properties, enums, and relational structures. FixtureKit automates this by generating mock data directly from the interface definition, ensuring that every field is populated with a realistic, type-compliant value. This eliminates manual effort, reduces bugs, and maintains a single source of truth between types and test data.

FixtureKit's primary feature is the automatic generation of mock data directly from TypeScript interfaces. Developers provide an interface definition, and FixtureKit returns a fully populated JavaScript/TypeScript object that matches the interface's structure and types. Each field is assigned a realistic default value based on its declared type: strings become plausible names or emails, numbers become integers or floats, and dates become ISO timestamps. Boolean fields receive random true/false values, while union types and enums are filled with one of the possible values. This automation eliminates the need to manually construct mock objects line by line, ensuring that the generated data is always type-compliant and instantly usable in tests, prototypes, or database seeding scripts.

FixtureKit generates realistic mock data using a built-in set of generators that create values resembling real-world data. For instance, the ID field in the PrismaUser example is a valid UUID, the email is a correctly formatted address, and the names are plausible first and last names. Timestamps are provided in ISO format, and enum fields like 'role' are assigned one of the valid enum values. This realism makes FixtureKit ideal for demos and testing where data authenticity matters. Developers can trust that the output looks natural in UI mockups and behaves correctly in database operations. The generators are designed to produce varied output across multiple calls, ensuring diversity in test datasets.