Plugin makes webpack --json output invalid

[manuelbieh]

Hi,

when using friendly-errors-webpack-plugin with webpack --json the generated JSON is invalid:

 DONE  Compiled successfully in 21858ms12:59:37

{
  "errors": [],
  "warnings": [],
  "version": "2.3.2",
  "hash": "0837132c83435ec275e9",
  "time": 21858,
  "publicPath": "/",
...

Maybe you can add a check if --json flag is set and omit the compilation message? Otherwise it's impossible to pipe the webpack --json output to other tools such as webpack-bundle-size-analyzer:

$ webpack --json | webpack-bundle-size-analyzer
Error: The input is not valid JSON.

Check that:
 - You passed the '--json' argument to 'webpack'
 - There is no extra non-JSON content in the output, such as log messages.

The parsing error was:

  SyntaxError: Unexpected token D in JSON at position 1

[manuelbieh]

https://github.com/geowarin/friendly-errors-webpack-plugin/blob/master/src/output.js#L52

Changing this line to

if (this.enabled && process.argv.indexOf('--json') === -1) {

solves my problem for now.