feat: add --quiet flag to suppress No depcheck issue messages

Closes #759

README.md

@@ -92,6 +92,8 @@ All of the arguments are optional:
 
 `--ignore-patterns`: Comma separated patterns describing files to ignore. Patterns must match the .gitignore [spec](http://git-scm.com/docs/gitignore). Example, `--ignore-patterns=build/Release,dist,coverage,*.log`.
 
+`--quiet`: Suppress the "No depcheck issue" log. Useful in a monorepo with multiple packages to focus only on packages with issues.
+
 `--help`: Show the help message.
 
 `--parsers`, `--detectors` and `--specials`: These arguments are for advanced usage. They provide an easy way to customize the file parser and dependency detection. Check [the pluggable design document](https://github.com/depcheck/depcheck/blob/master/doc/pluggable-design.md) for more information.

src/cli.js

@@ -86,7 +86,7 @@ function print(result, log, opt, rootDir) {
         lodash.isError(value) ? value.stack : value,
       ),
     );
-  } else if (noIssue(result)) {
+  } else if (noIssue(result) && !opt.quiet) {
     log('No depcheck issue');
   } else {
     const deps = prettify(

src/utils/configuration-reader.js

@@ -48,6 +48,7 @@ export function getCliArgs(args, version) {
       'Comma separated patterns describing files to ignore.',
     )
     .describe('parsers', 'Comma separated glob:parser pair list')
+    .describe('quiet', 'Suppress the "No depcheck issue" message')
     .describe('detectors', 'Comma separated detector list')
     .describe('specials', 'Comma separated special parser list')
     .version('version', 'Show version number', version)

test/cli.js

@@ -16,6 +16,10 @@ function makeArgv(module, options) {
     argv.push('--json');
   }
 
+  if (options.quiet) {
+    argv.push('--quiet');
+  }
+
   if (typeof options.ignoreBinPackage !== 'undefined') {
     argv.push(`--ignore-bin-package=${options.ignoreBinPackage}`);
   }
@@ -162,6 +166,15 @@ describe('depcheck command line', () => {
       },
     ));
 
+  it('should output no depcheck issue when happen', () =>
+    testCli(makeArgv('good', { quiet: true })).then(
+      ({ log, error, exitCode }) => {
+        log.should.equal('');
+        error.should.be.empty();
+        exitCode.should.equal(0);
+      },
+    ));
+
   it('should output unused dependencies', () =>
     testCli(makeArgv('bad', {})).then(({ logs, error, exitCode }) => {
       logs.should.have.length(2);