@bufbuild/cel

@bufbuild/cel

This package provides a CEL evaluator for ECMAScript.

Example

Let's evaluate a CEL expression that has the variable name and uses the strings extension functions:

import { run } from "@bufbuild/cel";
import { strings } from "@bufbuild/cel/ext";

run(
  `name.indexOf('taco') == 0`, // CEL expression to run
  { name: "tacocat" }, // Bind a value to the variable `name`
  { funcs: strings }, // Register `indexOf` and other string extensions
); // true

That's it!

For an example of creating a reusable evaluator and more, refer to example.ts.

Types

The table below maps JS types to CEL types.

• Input column is any value that can be passed to the evaluator as input. (CelInput)
• CEL Type column is the CEL type it will represent at runtime. (CelType)
• Output column is the type of values that are returned by the evaluator, either as returned from eval or as arguments to function implementations. (CelValue)