Effect Dual
In the context of APIs, “dual” refers to a function that supports both the “data-first” and “data-last” variants. It means that the API can be used interchangeably with either style, depending on the developer’s preference.
One example of a dual API is the andThen function of the Effect data type.
In the “data-first” variant, the effect is passed as the first argument to andThen:
import { Effect } from 'effect';
Effect.andThen(Effect.succeed(1), (n) => n + 1);
What is dual function in Effect?
This dual function in Effect is particularly useful in a static-typed language like TypeScript where defining function types enhance code reliability. By providing various function signatures, this function can have different ways without having to create multiple functions for each specialized case. here video: