Handle boolean checkSyntacticErrors option correctly when passed in

Author: johnnyreilly

lib/index.js

@@ -31,8 +31,8 @@ function ForkTsCheckerWebpackPlugin (options) {
   this.logger = options.logger || console;
   this.silent = options.silent === true; // default false
   this.async = options.async !== false; // default true
+  this.checkSyntacticErrors = options.checkSyntacticErrors === true; // default false
   this.workersNumber = options.workers || ForkTsCheckerWebpackPlugin.ONE_CPU;
-  this.checkSyntacticErrors = options.checkSyntacticErrors || false; // default false
   this.memoryLimit = options.memoryLimit || ForkTsCheckerWebpackPlugin.DEFAULT_MEMORY_LIMIT;
   this.useColors = options.colors !== false; // default true
   this.colors = new chalk.constructor({ enabled: this.useColors });