fix: add config values to hash salt (#988)

Fixes #522

index.js

@@ -99,7 +99,7 @@ function NYC (config) {
 
 NYC.prototype._createTransform = function (ext) {
   var opts = {
-    salt: Hash.salt,
+    salt: Hash.salt(this.config),
     hashData: (input, metadata) => [metadata.filename],
     onHash: (input, metadata, hash) => {
       this.hashCache[metadata.filename] = hash

lib/hash.js

@@ -1,8 +1,30 @@
 'use strict'
 
+function getInvalidatingOptions (config) {
+  return [
+    'compact',
+    'esModules',
+    'ignoreClassMethods',
+    'instrument',
+    'instrumenter',
+    'plugins',
+    'preserveComments',
+    'produceSourceMap',
+    'sourceMap'
+  ].reduce((acc, optName) => {
+    acc[optName] = config[optName]
+    return acc
+  }, {})
+}
+
 module.exports = {
-  salt: JSON.stringify({
-    istanbul: require('istanbul-lib-coverage/package.json').version,
-    nyc: require('../package.json').version
-  })
+  salt (config) {
+    return JSON.stringify({
+      modules: {
+        'istanbul-lib-instrument': require('istanbul-lib-instrument/package.json').version,
+        nyc: require('../package.json').version
+      },
+      nycrc: getInvalidatingOptions(config)
+    })
+  }
 }