getdtl.org

What It Is

DTL (Data Transformation Language) is a toolkit for data manipulation and transformation, designed to replace hand-written scripts with declarative transformation rules. It can process batch data from the command line and can also be used in Node.js, on the server side, and in the browser. It is suited to data migration, batch processing, ETL, form or API input transformation, and scenarios where the same set of calculation rules needs to be shared between frontend and backend.

Core Capabilities and Ecosystem

DTL is centered on describing “how to transform one set of data into another,” while also supporting input validation and complex calculations. The CLI tool dtl can handle input and output for JSON, JSONLines, YAML, and CSV, with support for filtering, sorting, grouping, and complex structured-data operations. Its positioning is similar to grep, awk, sed, and sort, but for complex data structures. The dtlr REPL includes built-in help, making it useful for learning the syntax and exploring interactively. In code, the npm package dtl-js can be required in Node.js, with transformations applied via dtl.apply(input, transform). In the browser, you can use the build files included in the npm package or load it via the jsDelivr CDN. Since version 5.0.0, mathematical computation has used arbitrary precision based on bignumber.js, reducing JavaScript floating-point errors.

Security, Pricing, and Documentation

DTL emphasizes safe execution: transformation rules cannot access the external environment, file system, or libraries, making it suitable for running transformation and calculation logic provided by third parties. The main text does not specify a license, so it is not possible to confirm whether it is open source or closed source; it also does not mention commercial pricing, paid support, or an enterprise edition. For documentation, the website mentions syntax documentation, a helper reference, and advanced-topic docs, and the REPL supports .help for viewing function help. Overall, its basic usability appears solid.

Pros, Cons, and Who It’s For

Its strengths include JavaScript compatibility, flexible runtime options, support for common structured data formats, and the ability to store and migrate transformation logic as JSON rules. The downsides are that users need to learn a dedicated syntax, and the main text lacks information on licensing, maintenance activity, production use cases, and service support. It is suitable for JS developers, data engineers, and teams that need to execute configurable transformation rules safely.

Access from China

The main text does not provide information about access from mainland China, mirrors, or payment options, so accessibility from China should be considered unknown. In practice, usage mainly depends on npm/yarn and jsDelivr, which may be affected by network quality in domestic environments. Alternatives to consider include jq, yq, JSONata, Jolt, or implementing the logic directly with Node.js scripts.