fix: add negative lookbehind for comment in static import regex

[stevezhu]

Description

The static import regex is missing an exclusion for the case where the import statement is a comment. The esm shim will be added below the comment instead of the actual last import statement in this case. I didn't spend much time on the regex edit, so if there's a better implementation, please make any suggestions for improvements!

Changed the regex to ensure start of line(?<=^(|\s|;)). Not sure if this is valid for all cases. For example, an invalid case where you have a space before the semicolon:

// whitespace at start of line
 ;import __cjs_url__ from 'node:url';

An alternative is using a negative lookbehind for // ((?<!\/\/.*?)) which can be seen in the first commit:

const ESMStaticImportRe =
-  /(?<=\s|^|;)import\s*([\s"']*(?<imports>[\p{L}\p{M}\w\t\n\r $*,/{}@.]+)from\s*)?["']\s*(?<specifier>(?<="\s*)[^"]*[^\s"](?=\s*")|(?<='\s*)[^']*[^\s'](?=\s*'))\s*["'][\s;]*/gmu
const ESMStaticImportRe =
+  /(?<!\/\/.*?)(?<=\s|^|;)import\s*([\s"']*(?<imports>[\p{L}\p{M}\w\t\n\r $*,/{}@.]+)from\s*)?["']\s*(?<specifier>(?<="\s*)[^"]*[^\s"](?=\s*")|(?<='\s*)[^']*[^\s'](?=\s*'))\s*["'][\s;]*/gmu

Additional context

I ran into this issue where it added the esm shim under the comment below instead. I didn't test thoroughly but it seems like the esm shim plugin runs before comments are removed in the build process.

Example:

// import { $ZodType } from "./schemas.js";
// esm shim would be added here
const $ZodCheck = /*@__PURE__*/ $constructor("$ZodCheck", (inst, def) => {
    var _a;
    inst._zod ?? (inst._zod = {});
    inst._zod.def = def;
    (_a = inst._zod).onattach ?? (_a.onattach = []);
});

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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