__Pure__ annotation in Zod source code.

In this article, we will review Pureannotation in zod source code. 

We will look at:

1. Where to find pure annotation in Zod source code?

2. pure annotations issue in evanw/esbuild.

Where to find pure annotation in Zod source code?

You will find pureannotation in zod source code at this location- https://github.com/colinhacks/zod/blob/main/packages/zod/src/v4/classic/parse.ts#L20C35-L20C44]

export const parseAsync: <T extends core.$ZodType>(
  schema: T,
  value: unknown,
  _ctx?: core.ParseContext<core.$ZodIssue>,
  _params?: { callee?: core.util.AnyFunc; Err?: core.$ZodErrorClass }
) => Promise<core.output<T>> = /* @__PURE__ */ core._parseAsync(ZodRealError) as any;

pure annotations issue in evanw/esbuild

You will find an issue related to pureannotations in esbuild repository.

Issue 503

Below is the issue description:

Currently, the /* @__PURE__ */ annotation must be used individually on every returned value for a given call. 

Could it be possible to allow using the annotation on a function, so all its returned values are considered pure? Like in the following.

/**
 * The function is pure, so if the result is not used, it can be removed.
 * 
 * @__PURE__
 */
function addTwo(number: number) {
    return number + 2;
}
 
// Will be removed
addTwo(4);
 
// Will be removed
const x = addTwo(3);
 
// This will be kept
export const y = addTwo(2);

this is what @evanw had to say

About me:

Hey, my name is Ramu Narasinga. I study large open-source projects and create content about their codebase architecture and best practices, sharing it through articles, videos.

Build Shadcn CLI from scratch.

Email — ramu@thinkthroo.com

My Github —  https://github.com/ramu-narasinga

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References

1. https://github.com/colinhacks/zod/blob/main/packages/zod/src/v4/classic/parse.ts#L20C35-L20C44

2. https://github.com/evanw/esbuild/issues/1883