feat: allow users to import from node_modules (#1021)

packages/schema/src/utils/ast-utils.ts

@@ -18,6 +18,8 @@ import {
 import { isFromStdlib } from '@zenstackhq/sdk';
 import { AstNode, getDocument, LangiumDocuments, Mutable } from 'langium';
 import { URI, Utils } from 'vscode-uri';
+import { findNodeModulesFile } from './pkg-utils';
+import {isAbsolute} from 'node:path'
 
 export function extractDataModelsWithAllowRules(model: Model): DataModel[] {
     return model.declarations.filter(
@@ -94,15 +96,21 @@ export function getDataModelFieldReference(expr: Expression): DataModelField | u
 }
 
 export function resolveImportUri(imp: ModelImport): URI | undefined {
-    if (imp.path === undefined || imp.path.length === 0) {
-        return undefined;
+    if (!imp.path) return undefined; // This will return true if imp.path is undefined, null, or an empty string ("").
+
+    if (!imp.path.endsWith('.zmodel')) {
+        imp.path += '.zmodel';
     }
-    const dirUri = Utils.dirname(getDocument(imp).uri);
-    let grammarPath = imp.path;
-    if (!grammarPath.endsWith('.zmodel')) {
-        grammarPath += '.zmodel';
+
+    if (
+        !imp.path.startsWith('.') // Respect relative paths
+        && !isAbsolute(imp.path) // Respect Absolute paths
+    ) {
+        imp.path = findNodeModulesFile(imp.path) ?? imp.path;
     }
-    return Utils.resolvePath(dirUri, grammarPath);
+
+    const dirUri = Utils.dirname(getDocument(imp).uri);
+    return Utils.resolvePath(dirUri, imp.path);
 }
 
 export function resolveTransitiveImports(documents: LangiumDocuments, model: Model): Model[] {

packages/schema/src/utils/pkg-utils.ts

@@ -5,18 +5,18 @@ import { execSync } from './exec-utils';
 export type PackageManagers = 'npm' | 'yarn' | 'pnpm';
 
 /**
- * A type named FindUp that takes a type parameter e which extends boolean. 
- * If e extends true, it returns a union type of string[] or undefined. 
+ * A type named FindUp that takes a type parameter e which extends boolean.
+ * If e extends true, it returns a union type of string[] or undefined.
  * If e does not extend true, it returns a union type of string or undefined.
  *
  * @export
  * @template e A type parameter that extends boolean
  */
 export type FindUp<e extends boolean> = e extends true ? string[] | undefined : string | undefined
 /**
- * Find and return file paths by searching parent directories based on the given names list and current working directory (cwd) path. 
- * Optionally return a single path or multiple paths. 
- * If multiple allowed, return all paths found. 
+ * Find and return file paths by searching parent directories based on the given names list and current working directory (cwd) path.
+ * Optionally return a single path or multiple paths.
+ * If multiple allowed, return all paths found.
  * If no paths are found, return undefined.
  *
  * @export
@@ -37,6 +37,30 @@ export function findUp<e extends boolean = false>(names: string[], cwd: string =
     return findUp(names, up, multiple, result);
 }
 
+
+/**
+ * Find a Node module/file given its name in a specific directory, with a fallback to the current working directory.
+ * If the name is empty, return undefined.
+ * Try to resolve the module/file using require.resolve with the specified directory as the starting point.
+ * Return the resolved path if successful, otherwise return undefined.
+ *
+ * @export
+ * @param {string} name The name of the module/file to find
+ * @param {string} [cwd=process.cwd()]
+ * @returns {*} Finds a specified module or file using require.resolve starting from a specified directory path, or the current working directory if not provided.
+ */
+export function findNodeModulesFile(name: string, cwd: string = process.cwd()) {
+    if (!name) return undefined;
+    try {
+        // Use require.resolve to find the module/file. The paths option allows specifying the directory to start from.
+        const resolvedPath = require.resolve(name, { paths: [cwd] })
+        return resolvedPath
+    } catch (error) {
+        // If require.resolve fails to find the module/file, it will throw an error.
+        return undefined
+    }
+}
+
 function getPackageManager(projectPath = '.'): PackageManagers {
     const lockFile = findUp(['yarn.lock', 'pnpm-lock.yaml', 'package-lock.json'], projectPath);
 
@@ -106,7 +130,7 @@ export function ensurePackage(
 }
 
 /**
- * A function that searches for the nearest package.json file starting from the provided search path or the current working directory if no search path is provided. 
+ * A function that searches for the nearest package.json file starting from the provided search path or the current working directory if no search path is provided.
  * It iterates through the directory structure going one level up at a time until it finds a package.json file. If no package.json file is found, it returns undefined.
  * @deprecated Use findUp instead @see findUp
  */