More docs for import maps

src/check.js

@@ -44,6 +44,15 @@ function detect(detectors, node, deps) {
 // dependency starts with '#' and we have a matching entry in "imports" in
 // the package.json we'll substitute the possible mapped imports in place of
 // that dependency.
+//
+// Conditions can be well-known ones implemented by node, TypeScript, or webpack like
+// "import", "browser", "types", or "require".  They can also be custom ones as configurable
+// in webpack configuration or using the enhanced-resolve package.
+//
+// See also:
+//   - https://nodejs.org/api/packages.html#subpath-imports
+//   - https://www.typescriptlang.org/docs/handbook/esm-node.html
+//   - https://webpack.js.org/configuration/resolve/#resolveconditionnames
 function applyImportsMap(importsMap, dep) {
   const resolvedDeps = [];