RFC: bin/run: Add --reporter-options

This PR depends on tapjs/tap-mocha-reporter#49; review that first.

This is inspired by [Mocha's][1]:

```
  --reporter-options <k=v,k2=v2,...>
```

Except:

* I'm using a JSON value for easier parsing and more explicit typing.
  This will end up using a few more characters, but the format is more
  explicit than Mocha's (which only uses string values?).  And callers
  are likely to already be familiar with JSON, so we save the mental
  overhead of teaching them a new serialization format.

* I'm using a 'reporter' namespace.  This allows us to add other
  namespaces in the future to address other configurable aspects of
  tap-mocha-reporter's Formatter.  For example, we could use this
  same CLI option to configure the runner.

Somewhat related to this, if we have plans for allowing multiple
reporters [2], we may want to namespace *those* now.  For example:

```
  --reporter-options {"reporter": {"progress": {"open": "(", "close": ")"}}}
```

to avoid the issues Mocha bumped into [3] when trying to add multi-reporter support.

[1]: https://mochajs.org/#usage
[2]: tapjs#335
[3]: mochajs/mocha#2184 (comment)

bin/run.js

@@ -127,6 +127,7 @@ const constructDefaultArgs = _ => {
     timeout: +process.env.TAP_TIMEOUT || defaultTimeout,
     color: !!colorSupport.level,
     reporter: null,
+    reporterOptions: {},
     files: [],
     grep: [],
     grepInvert: false,
@@ -282,6 +283,10 @@ const parseArgs = (args, options) => {
         options.reporter = val || args[++i]
         continue
 
+      case '--reporter-options':
+        options.reporterOptions = JSON.parse(val || args[++i])
+        continue
+
       case '--gc': case '-gc': case '--expose-gc':
         options.nodeArgs.push('--expose-gc')
         continue
@@ -595,9 +600,9 @@ const setupTapEnv = options => {
 const globFiles = files => files.reduce((acc, f) =>
   acc.concat(f === '-' ? f : glob.sync(f, { nonull: true })), [])
 
-const makeReporter = options =>
-  new (require('tap-mocha-reporter'))(options.reporter)
-
+const makeReporter = options => {
+  return new (require('tap-mocha-reporter'))(options.reporter, {}, options.reporterOptions)
+}
 const stdinOnly = options => {
   // if we didn't specify any files, then just passthrough
   // to the reporter, so we don't get '/dev/stdin' in the suite list.

bin/usage.txt

@@ -62,6 +62,11 @@ Options:
                               Available reporters:
 @@REPORTERS@@
 
+  --reporter-options=<opts>   Configure the specified reporter with a
+                              JSON value.  For example, you could use
+                              '{"reporter": {"open": "(", "close": ")"}}'
+                              to customize the progress reporter.
+
   -o<file>                    Send the raw TAP output to the specified
   --output-file=<file>        file.  Reporter output will still be
                               printed to stdout, but the file will

docs/cli/index.md

@@ -74,6 +74,11 @@ Options:
                               landing list markdown min nyan progress
                               silent spec tap xunit
 
+  --reporter-options=<opts>   Configure the specified reporter with a
+                              JSON value.  For example, you could use
+                              `{"reporter": {"open": "(", "close": ")"}}`
+                              to customize the progress reporter.
+
   -o<file>                    Send the raw TAP output to the specified
   --output-file=<file>        file.  Reporter output will still be
                               printed to stdout, but the file will

docs/reporting/index.md

@@ -86,3 +86,11 @@ The following options are available:
 - xunit
 
     XML output popular in .NET land.
+
+You can pass options to those reporters using `--reporter-options`
+with a JSON value.  For example:
+
+```
+--reporter=progress
+--reporter-options='{"reporter": {"open": "(", "close": ")"}}'
+```

package.json

@@ -34,7 +34,7 @@
     "signal-exit": "^3.0.0",
     "source-map-support": "^0.5.6",
     "stack-utils": "^1.0.0",
-    "tap-mocha-reporter": "^3.0.7",
+    "tap-mocha-reporter": "FIXME: bump to contain https://github.com/tapjs/tap-mocha-reporter/pull/49 once it lands",
     "tap-parser": "^7.0.0",
     "tmatch": "^4.0.0",
     "trivial-deferred": "^1.0.1",