fix: upgrade convert-source-map (#224)

lib/v8-to-istanbul.js

@@ -9,6 +9,7 @@ const CovFunction = require('./function')
 const CovSource = require('./source')
 const { sliceRange } = require('./range')
 const compatError = Error(`requires Node.js ${require('../package.json').engines.node}`)
+const { readFileSync } = require('fs')
 let readFile = () => { throw compatError }
 try {
   readFile = require('fs').promises.readFile
@@ -49,7 +50,7 @@ module.exports = class V8ToIstanbul {
       // if we find a source-map (either inline, or a .map file) we load
       // both the transpiled and original source, both of which are used during
       // the backflips we perform to remap absolute to relative positions.
-      convertSourceMap.fromSource(rawSource) || convertSourceMap.fromMapFileSource(rawSource, dirname(this.path))
+      convertSourceMap.fromSource(rawSource) || convertSourceMap.fromMapFileSource(rawSource, this._readFileFromDir.bind(this))
 
     if (this.rawSourceMap) {
       if (this.rawSourceMap.sourcemap.sources.length > 1) {
@@ -89,6 +90,10 @@ module.exports = class V8ToIstanbul {
     }
   }
 
+  _readFileFromDir (filename) {
+    return readFileSync(resolve(dirname(this.path), filename), 'utf-8')
+  }
+
   async sourcesContentFromSources () {
     const fileList = this.sourceMap.sources.map(relativePath => {
       const realPath = this._resolveSource(this.rawSourceMap, relativePath)

package.json

@@ -27,7 +27,7 @@
   "dependencies": {
     "@jridgewell/trace-mapping": "^0.3.12",
     "@types/istanbul-lib-coverage": "^2.0.1",
-    "convert-source-map": "^1.6.0"
+    "convert-source-map": "^2.0.0"
   },
   "devDependencies": {
     "@types/node": "^18.0.0",