fix: ignore all Types from TypeScript and not executable lines

Author: anthony-redFox

index.js

@@ -1,5 +1,5 @@
 const V8ToIstanbul = require('./lib/v8-to-istanbul')
 
-module.exports = function (path, wrapperLength, sources, excludePath) {
-  return new V8ToIstanbul(path, wrapperLength, sources, excludePath)
+module.exports = function (path, wrapperLength, sources, excludePath, plugin) {
+  return new V8ToIstanbul(path, wrapperLength, sources, excludePath, plugin)
 }

lib/plugin.js

@@ -0,0 +1,36 @@
+const esbuild = require('esbuild');
+const vlq = require('vlq');
+
+module.exports = function (source, resolvedPath) {
+    let result
+    try {
+        const loader = path.endsWith('.tsx') || path.endsWith('.jsx') ? { loader: 'tsx', jsx: 'preserve' } : {}
+        result = esbuild.transformSync(source.sourceRaw, {
+          sourcemap: 'external',
+          loader: 'ts',
+          minify: false,
+          minifyWhitespace: false,
+          minifySyntax: false,
+          legalComments: 'none',
+          ...loader
+        })
+    } catch (err) {
+        console.error(`${resolvedPath} parsed with error ${err.message}`)
+        return;
+    }
+    const mappings = JSON.parse(result.map).mappings
+    if (mappings) {
+        let start = 0
+        const executableLines = mappings.split(';').reduce((set, str) => {
+            start = str.split(',').reduce((number, seg) => {
+                const [,,line] = vlq.decode(seg)
+                set.add(number + line)
+                return number + line
+            }, start)
+            return set
+        }, new Set())
+        source.lines.forEach((line, index) => 
+            line.ignore = line.ignore || !executableLines.has(index)
+        )
+    }
+}

lib/source.js

@@ -4,6 +4,7 @@ const { originalPositionFor, generatedPositionFor, GREATEST_LOWER_BOUND, LEAST_U
 
 module.exports = class CovSource {
   constructor (sourceRaw, wrapperLength) {
+    this.sourceRaw = sourceRaw;
     sourceRaw = sourceRaw ? sourceRaw.trimEnd() : ''
     this.lines = []
     this.eof = sourceRaw.length

lib/v8-to-istanbul.js

@@ -25,12 +25,13 @@ const isNode8 = /^v8\./.test(process.version)
 const cjsWrapperLength = isOlderNode10 ? require('module').wrapper[0].length : 0
 
 module.exports = class V8ToIstanbul {
-  constructor (scriptPath, wrapperLength, sources, excludePath) {
+  constructor (scriptPath, wrapperLength, sources, excludePath, plugin) {
     assert(typeof scriptPath === 'string', 'scriptPath must be a string')
     assert(!isNode8, 'This module does not support node 8 or lower, please upgrade to node 10')
     this.path = parsePath(scriptPath)
     this.wrapperLength = wrapperLength === undefined ? cjsWrapperLength : wrapperLength
     this.excludePath = excludePath || (() => false)
+    this.plugin = plugin
     this.sources = sources || {}
     this.generatedLines = []
     this.branches = {}
@@ -260,6 +261,10 @@ module.exports = class V8ToIstanbul {
       return
     }
 
+    if (this.plugin) {
+      this.plugin(source, resolvedPath)
+    }
+
     return {
       [resolvedPath]: {
         path: resolvedPath,