feat(quiet): added -q/--quiet to suppress output from npx itself

Author: zkat

README.md

@@ -42,6 +42,8 @@ If a full specifier is included, or if `--package` is used, npx will always use
 
 * `--ignore-existing` - If this flag is set, npx will not look in `$PATH`, or in the current package's `node_modules/.bin` for an existing version before deciding whether to install. Binaries in those paths will still be available for execution, but will be shadowed by any packages requested by this install.
 
+* `-q, --quiet` - Suppressed any output from npx itself (progress bars, error messages, install reports). Subcommand output itself will not be silenced.
+
 * `-v, --version` - Show the current npx version.
 
 ## EXAMPLES

index.js

@@ -26,8 +26,8 @@ function main (argv) {
   }
 
   if (!argv.call && (!argv.command || !argv.package)) {
-    console.error(Y()`\nERROR: You must supply a command.\n`)
-    parseArgs.showHelp()
+    !argv.q && console.error(Y()`\nERROR: You must supply a command.\n`)
+    !argv.q && parseArgs.showHelp()
     process.exitCode = 1
     return
   }
@@ -65,7 +65,7 @@ function main (argv) {
         require('update-notifier')({pkg: require('./package.json')}).notify()
         // Some npm packages need to be installed. Let's install them!
         return ensurePackages(argv.package, argv).then(results => {
-          results && console.error(Y()`npx: installed ${
+          results && !argv.q && console.error(Y()`npx: installed ${
             results.added.length + results.updated.length
           } in ${(Date.now() - startTime) / 1000}s`)
         }).then(() => existing)
@@ -85,7 +85,7 @@ function main (argv) {
         }
       })
     }).catch(err => {
-      console.error(err.message)
+      !argv.q && console.error(err.message)
       process.exitCode = err.exitCode || 1
     })
   })
@@ -168,7 +168,7 @@ function installPackages (specs, prefix, opts) {
   const args = buildArgs(specs, prefix, opts)
   return which(opts.npm).then(npmPath => {
     return child.spawn(npmPath, args, {
-      stdio: [0, 'pipe', 2]
+      stdio: [0, 'pipe', opts.q ? 'ignore' : 2]
     }).then(deets => {
       try {
         return deets.stdout ? JSON.parse(deets.stdout) : null

parse-args.js

@@ -88,6 +88,11 @@ function parseArgs (argv) {
     describe: Y()`Ignores existing binaries in $PATH, or in the local project. This forces npx to do a temporary install and use the latest version.`,
     type: 'boolean'
   })
+  .option('quiet', {
+    alias: 'q',
+    describe: Y()`Suppress output from npx itself. Subcommands will not be affected.`,
+    type: 'boolean'
+  })
   .option('npm', {
     describe: Y()`npm binary to use for internal operations.`,
     type: 'string',