fix: remove excluded files from coverage before writing (#649)

Author: princjef

index.js

@@ -367,6 +367,13 @@ NYC.prototype.writeCoverageFile = function () {
   var coverage = coverageFinder()
   if (!coverage) return
 
+  // Remove any files that should be excluded but snuck into the coverage
+  Object.keys(coverage).forEach(function (absFile) {
+    if (!this.exclude.shouldInstrument(absFile)) {
+      delete coverage[absFile]
+    }
+  }, this)
+
   if (this.cache) {
     Object.keys(coverage).forEach(function (absFile) {
       if (this.hashCache[absFile] && coverage[absFile]) {