@jsenv/import-map/src/resolveSpecifier.js

Helpers to implement importmaps.

import { hasScheme } from "./internal/hasScheme.js"
import { resolveUrl } from "./resolveUrl.js"

export const resolveSpecifier = (specifier, importer) => {
  if (
    specifier === "." ||
    specifier[0] === "/" ||
    specifier.startsWith("./") ||
    specifier.startsWith("../")
  ) {
    return resolveUrl(specifier, importer)
  }

  if (hasScheme(specifier)) {
    return specifier
  }

  return null
}