Html Webpack Plugin:
  TypeError: Cannot read property 'length' of undefined
  
  - index.js:78 initRegExp
    [test]/[html-webpack-plugin-custom]/index.js:78:30
  
  - index.js:58 initOpt
    [test]/[html-webpack-plugin-custom]/index.js:58:26
  
  - index.js:39 Compilation.
    [test]/[html-webpack-plugin-custom]/index.js:39:13
  
  - Tapable.js:86 Compilation.applyPluginsAsyncWaterfall
    [test]/[tapable]/lib/Tapable.js:86:13
  
  - util.js:16 Compilation.tryCatcher
    [test]/[bluebird]/js/release/util.js:16:23
  
  
  - index.js:642 
    [test]/[html-webpack-plugin]/index.js:642:12
  
  - index.js:166 
    [test]/[html-webpack-plugin]/index.js:166:16
  
  - util.js:16 tryCatcher
    [test]/[bluebird]/js/release/util.js:16:23
  
  - promise.js:510 Promise._settlePromiseFromHandler
    [test]/[bluebird]/js/release/promise.js:510:31
  
  - promise.js:567 Promise._settlePromise
    [test]/[bluebird]/js/release/promise.js:567:18
  
  - promise.js:612 Promise._settlePromise0
    [test]/[bluebird]/js/release/promise.js:612:10
  
  - promise.js:691 Promise._settlePromises
    [test]/[bluebird]/js/release/promise.js:691:18
  
  - async.js:133 Async._drainQueue
    [test]/[bluebird]/js/release/async.js:133:16
  
  - async.js:143 Async._drainQueues
    [test]/[bluebird]/js/release/async.js:143:10
  
  - async.js:17 Immediate.Async.drainQueues
    [test]/[bluebird]/js/release/async.js:17:14