github.com/renato-bohler/what-the-filter ↗
A visual playground to JavaScript array & object transformations.
Open this visualization on its own page →
Contributors
1
Lines of Code
91
From
2020-11-24
To
2020-12-03
About renato-bohler/what-the-filter
What the Filter is a visual playground for understanding JavaScript array and object transformations. It lets users write transformation code and immediately see an informative diagram showing how the data flows through each operation in the chain.
The tool works by parsing user code into an abstract syntax tree to analyze which methods are called, what arguments they receive, and how the data transforms at each step. This makes it easy to visualize complex chains of operations like filter, map, reduce, and other array or object methods. The playground is interactive and runs directly in the browser, accessible through a live web interface.
Beyond basic visualization, the tool includes several helpful features for learning and debugging. It shows detailed error messages with execution steps up to the point where an error occurs, provides step-by-step breakdowns for how certain methods transform their input into output, and offers warnings about JavaScript quirks and unexpected behavior. These features make it valuable for both beginners learning array methods and experienced developers wanting to verify complex transformation logic.