feat: Verbose as CLI flag

[montogeek]

As discussed on #126, I added verbose mode as CLI flag.
I am not sure about variables naming, but it works and tests pass.
I think it need more tests, let me know if should be necessary.

[sudo-suhas]

We are not transpiling the source code and destructuring objects isn't supported in node v4 and v6. Additionally, at this point the result.config isn't normalized. So it could be in the simple or advanced format. You can refer https://github.com/okonet/lint-staged#configuration to know more about configuration. If the type is simple, then adding the verbose flag to it would be incorrect.

[okonet]

@montogeek do you mind fixing the PR? I'd love to merge it!

[montogeek]

@sudo-suhas I do not understand what you mean, if the configuration have verbose it is advanced? So it means verbose CLI flag should be added when being normalized?

[sudo-suhas]

@montogeek Sorry I wasn't clear. So here's an example of a simple config:

{
  "*.js": ["my-cmd"]
}

And an advanced one:

{
  "linters": {
    "*.js": ["my-cmd"]
  },
  "verbose": true
}

The simple one is converted to the advanced format in getConfig.js:
https://github.com/okonet/lint-staged/blob/331d3c5773b8013892a903bfd35eb8634db85741/src/getConfig.js#L94-L99

And this would be the right place to introduce the verbose flag if we got it in the command line args.
Since we use the config.verbose for determining the renderer, we should use the cmd-line flag before that:

------------------------------- src/getConfig.js -------------------------------
index 7d0a0bb..e087ed9 100644
@@ -91,9 +91,9 @@ function unknownValidationReporter(config, example, option, options) {
  *  concurrent: boolean, chunkSize: number, gitDir: string, globOptions: {matchBase: boolean, dot: boolean}, linters: {}, subTaskConcurrency: number, renderer: string, verbose: boolean
  * }}
  */
-function getConfig(sourceConfig) {
+function getConfig(sourceConfig, verbose) {
   const config = defaultsDeep(
-    {}, // Do not mutate sourceConfig!!!
+    { verbose }, // Do not mutate sourceConfig!!!
     isSimple(sourceConfig) ? { linters: sourceConfig } : sourceConfig,
     defaultConfig
   )

This should also ensure that the command line flag overrides config if applicable.

[okonet]

@montogeek any updates on this one? It would be really great to have this. I'd also suggest to remove the config option verbose along with adding a deprecation message for it like here: https://github.com/okonet/lint-staged/pull/327/files#diff-c90c061ebd15a26a15830f7fcc0c7544R122

[sudo-suhas]

@okonet Why not support both?

[okonet]

@sudo-suhas I think it doesn't belong to the config, TBH. verbose is something you use when you have problems, not all the time. Am I missing some use cases?

[sudo-suhas]

What you are saying makes sense. But I have in fact, used the verbose flag in the config on occasion(with ava).