break: Fix source map (#113)

* fix sourcemap line number

* fix comment

* use espree

* fix function name

package.json

@@ -38,6 +38,7 @@
   ],
   "dependencies": {
     "@istanbuljs/load-nyc-config": "^1.1.0",
+    "espree": "^9.5.2",
     "istanbul-lib-instrument": "^5.1.0",
     "picocolors": "^1.0.0",
     "test-exclude": "^6.0.0"

src/index.ts

@@ -4,6 +4,7 @@ import { createInstrumenter } from 'istanbul-lib-instrument';
 import TestExclude from 'test-exclude';
 import { loadNycConfig } from '@istanbuljs/load-nyc-config';
 import picocolors from 'picocolors';
+import {createIdentitySourceMap} from "./source-map";
 
 const { yellow } = picocolors;
 
@@ -181,9 +182,13 @@ export default function istanbulPlugin(opts: IstanbulPluginOptions = {}): Plugin
       const filename = resolveFilename(id);
 
       if (testExclude.shouldInstrument(filename)) {
+        // Create a source map to combine with the source map of previous plugins
+        instrumenter.instrumentSync(srcCode, filename, createIdentitySourceMap(filename, srcCode))
+        const map = instrumenter.lastSourceMap();
+
+        // Instrument code using the source map of previous plugins
         const sourceMap = sanitizeSourceMap(this.getCombinedSourcemap());
         const code = instrumenter.instrumentSync(srcCode, filename, sourceMap);
-        const map = instrumenter.lastSourceMap();
 
         // Required to cast to correct mapping value
         return { code, map } as TransformResult;

src/source-map.ts

@@ -0,0 +1,19 @@
+import * as espree from 'espree'
+import {SourceMapGenerator} from 'source-map'
+
+
+export function createIdentitySourceMap(file: string, source: string) {
+    const gen = new SourceMapGenerator({ file });
+    const tokens = espree.tokenize(source, { loc: true, ecmaVersion: 'latest' });
+
+    tokens.forEach((token: any) => {
+        const loc = token.loc.start;
+        gen.addMapping({
+            source: file,
+            original: loc,
+            generated: loc
+        });
+    });
+
+    return JSON.parse(gen.toString())
+}

src/types.d.ts

@@ -51,3 +51,41 @@ declare module 'test-exclude' {
 
   export = TestExclude;
 }
+
+declare module 'espree' {
+  // https://github.com/eslint/espree#options
+  export interface Options {
+    comment?: boolean;
+    ecmaFeatures?: {
+      globalReturn?: boolean;
+      impliedStrict?: boolean;
+      jsx?: boolean;
+    };
+    ecmaVersion?:
+        | 3
+        | 5
+        | 6
+        | 7
+        | 8
+        | 9
+        | 10
+        | 11
+        | 12
+        | 2015
+        | 2016
+        | 2017
+        | 2018
+        | 2019
+        | 2020
+        | 2021
+        | 2022
+        | 2023
+        | 'latest';
+    loc?: boolean;
+    range?: boolean;
+    sourceType?: 'script' | 'module';
+    tokens?: boolean;
+  }
+  // https://github.com/eslint/espree#tokenize
+  export function tokenize(code: string, options?: Options): any;
+}