Merge pull request #2433 from asger-semmle/import-js-file

Approved by max-schaefer

Author: semmle-qlci

change-notes/1.24/analysis-javascript.md

@@ -6,6 +6,9 @@
   - [react](https://www.npmjs.com/package/react)
   - [Handlebars](https://www.npmjs.com/package/handlebars)
 
+- Imports with the `.js` extension can now be resolved to a TypeScript file,
+  when the import refers to a file generated by TypeScript.
+
 ## New queries
 
 | **Query**                                                                 | **Tags**                                                          | **Purpose**                                                                                                                                                                            |

javascript/ql/src/semmle/javascript/Modules.qll

@@ -83,9 +83,13 @@ abstract class Module extends TopLevel {
         result = c.(Folder).getJavaScriptFile("index")
       )
       or
-      // handle the case where the import path is missing an extension
+      // handle the case where the import path is missing the extension
       exists(Folder f | f = path.resolveUpTo(path.getNumComponent() - 1) |
         result = f.getJavaScriptFile(path.getBaseName())
+        or
+        // If a js file was not found look for a file that compiles to js
+        not exists(f.getJavaScriptFile(path.getBaseName())) and
+        result = f.getJavaScriptFile(path.getStem())
       )
     )
   }

javascript/ql/src/semmle/javascript/Paths.qll

@@ -205,6 +205,9 @@ abstract class PathExpr extends PathExprBase {
   /** Gets the base name of the folder or file this path refers to. */
   string getBaseName() { result = getValue().(PathString).getBaseName() }
 
+  /** Gets the stem, that is, base name without extension, of the folder or file this path refers to. */
+  string getStem() { result = getValue().(PathString).getStem() }
+
   /**
    * Gets the file or folder that the first `n` components of this path refer to
    * when resolved relative to the root folder of the given `priority`.

javascript/ql/test/library-tests/Modules/import-ts-with-js-extension.ts

@@ -0,0 +1,3 @@
+import { foo } from "./f.js";
+
+foo();

javascript/ql/test/library-tests/Modules/tests.expected

@@ -6,6 +6,7 @@ test_ImportSpecifiers
 | f.ts:1:8:1:8 | g | f.ts:1:8:1:8 | g |
 | g.ts:1:9:1:11 | foo | g.ts:1:9:1:11 | foo |
 | import-in-mjs.mjs:1:8:1:24 | exported_from_mjs | import-in-mjs.mjs:1:8:1:24 | exported_from_mjs |
+| import-ts-with-js-extension.ts:1:10:1:12 | foo | import-ts-with-js-extension.ts:1:10:1:12 | foo |
 | m/c.js:1:8:1:13 | * as b | m/c.js:1:13:1:13 | b |
 | tst.html:5:10:5:10 | f | tst.html:5:10:5:10 | f |
 | unresolved.js:1:8:1:8 | f | unresolved.js:1:8:1:8 | f |
@@ -43,6 +44,7 @@ test_getImportedName
 | f.ts:1:8:1:8 | g | default |
 | g.ts:1:9:1:11 | foo | foo |
 | import-in-mjs.mjs:1:8:1:24 | exported_from_mjs | default |
+| import-ts-with-js-extension.ts:1:10:1:12 | foo | foo |
 | tst.html:5:10:5:10 | f | default |
 | unresolved.js:1:8:1:8 | f | default |
 test_ExportDeclarations
@@ -65,6 +67,7 @@ test_getAnImportedModule
 | es2015_require.js | d.js |
 | f.ts | e.js |
 | g.ts | f.ts |
+| import-ts-with-js-extension.ts | f.ts |
 | m/c.js | b.js |
 test_getSourceNode
 | a.js:1:1:3:1 | export  ... n 23;\\n} | default | a.js:1:16:3:1 | functio ... n 23;\\n} |
@@ -87,13 +90,15 @@ test_Imports
 | f.ts:1:1:1:19 | import g from './e' | f.ts:1:15:1:19 | './e' | 1 |
 | g.ts:1:1:1:23 | import  ... m './f' | g.ts:1:19:1:23 | './f' | 1 |
 | import-in-mjs.mjs:1:1:1:46 | import  ... n-mjs'; | import-in-mjs.mjs:1:31:1:45 | 'export-in-mjs' | 1 |
+| import-ts-with-js-extension.ts:1:1:1:29 | import  ... /f.js"; | import-ts-with-js-extension.ts:1:21:1:28 | "./f.js" | 1 |
 | m/c.js:1:1:1:26 | import  ... '../b'; | m/c.js:1:20:1:25 | '../b' | 1 |
 | tst.html:5:3:5:20 | import f from 'a'; | tst.html:5:17:5:19 | 'a' | 1 |
 | unresolved.js:1:1:1:18 | import f from 'a'; | unresolved.js:1:15:1:17 | 'a' | 1 |
 test_NamedImportSpecifier
 | d.js:1:10:1:21 | default as g |
 | d.js:1:24:1:29 | x as y |
 | g.ts:1:9:1:11 | foo |
+| import-ts-with-js-extension.ts:1:10:1:12 | foo |
 test_GlobalVariableRef
 | a.js:5:31:5:31 | o |
 | exports.js:3:9:3:15 | exports |