Convex Cookbook: Dynamic Query Builders

The article provides a detailed guide on constructing dynamic queries in Convex, particularly when using TypeScript, to allow for flexibility based on runtime conditions. It illustrates the challenges faced when attempting to build a single query variable in TypeScript due to its type constraints, such as the inability to apply multiple indexes or orders within one query. To overcome these limitations, the article suggests a staged approach whereby different variables and types are used at each stage of query building—selecting a table, applying an index, and setting an order—before applying any post-filters or retrieving results. This method ensures that each step maintains type validity, effectively allowing for dynamic query building while adhering to TypeScript's requirements. The article emphasizes the importance of understanding the structure and limitations of queries to avoid runtime errors, and it provides code examples to demonstrate the transition from untyped JavaScript to type-safe TypeScript, ensuring readers can apply these principles when building Convex applications.