Using HtmlResWebpackPlugin meet an Error

[zD98]

My webpack config

new HtmlResWebpackPlugin({
      mode: 'html',
      filename: config.build.index,
      template: "index.html",
      inject: true,
      chunks: 
        {
          'app.js':{}
        }
    }),

And I meet a Error

Unhandled rejection TypeError: htmlContent.replace is not a function

I log the console.log(typeof compilation.assets[this.options.htmlFileName].source()), it is a function, but it should be a string.
So How do I fix this error

[lcxfs1991]

please tell me your webpack version.

[zD98]

webpack@3.1.0
and this.options.htmlFileName's value is xxxx/dist/index.html