fix(help): allow printing for invalid commands

When an invalid subcommand is used, you can pass `data.argv.remain`
to the `help` command's run function and it will make it visible
what the error is.

Semver: patch

lib/commands/help.js

@@ -39,15 +39,37 @@ module.exports = new Command({
     })
 
     const commands = require('./')
-    const cls = lookup.length
+    let cls = lookup.length
       ? commands.resolve(lookup)
       : commands.get(cmd)
 
+    let output = []
+    if (cls === undefined && lookup.length) {
+      while (cls === undefined && lookup.length) {
+        // This means the last lookup failed.
+        // So, pop it off
+        const bad_command = lookup.pop()
+        const pre_command = conf.get('name') + ' ' + lookup.join(' ')
+        const len = pre_command.length + 1
+        output = [
+          'Invalid command:'
+        , ''
+        , `$ ${pre_command} ${this.colorize('red', bad_command)}`
+        , '-'.repeat(len + 2) + '^'.repeat(bad_command.length)
+        , ''
+        , `Below is the usage for ${this.colorize('bold', pre_command)}:`
+        , ''
+        ]
+
+        cls = commands.resolve(lookup)
+      }
+    }
+
     const instance = HELP_REGEX.test(cmd)
       ? this
       : typeof cls === 'function' ? new cls() : cls
 
-    let output = [instance.description]
+    output.push(instance.description)
 
     try {
       const breaker = '='.repeat(instance.description.length)

test/command.spec.js

@@ -74,8 +74,8 @@ test('command', async (t) => {
   })
 
   // usage parsing
-  t.test('~usage', async (tt) => {
-    test('should accept a single string', async (t) => {
+  t.test('~usage', async (t) => {
+    t.test('should accept a single string', async (t) => {
       const UsageCommand = new Command({
         usage: "usage -a 'fake' --verbose"
       , args: ['--no-color']
@@ -104,7 +104,7 @@ test('command', async (t) => {
       commands.unregister('usage')
     })
 
-    test('should accept an array of strings', async (t) => {
+    t.test('should accept an array of strings', async (t) => {
       const UsageCommand = new Command({
         usage: [
           "usage -a 'fake' --verbose"
@@ -116,6 +116,56 @@ test('command', async (t) => {
       const stdout = fs.readFileSync(fixture_path, 'utf8')
       t.equal(strip(UsageCommand.usage), stdout)
     })
+
+    t.test('handles missing subcommands', async (t) => {
+      const a = new Command({
+        name: 'a'
+      , usage: ['get a']
+      , run: async function() {}
+      })
+
+      const b = new Command({
+        name: 'b'
+      , usage: ['get b']
+      , run: async function() {}
+      })
+
+      const CmdA = new Command({
+        name: 'get'
+      , usage: [
+          ...a.options.usage
+        , ...b.options.usage
+        ]
+      , commands: [a, b]
+      , run: async function(cmd, flags) {
+          if (cmd && !this.has(cmd)) {
+            const error = new Error(`unknown waves action ${cmd}`)
+            error.code = 'ENOCOMMAND'
+            throw error
+          }
+
+          const help = cli.commands.get('help')
+          console.log(flags.argv.remain)
+          return help.run(flags.argv.remain)
+        }
+      })
+
+      commands.register(CmdA)
+      t.on('end', () => {
+        commands.unregister('get')
+      })
+      Help.removeAllListeners()
+      Help.reset()
+      Help.setOptions({
+        args: ['--no-color', 'get', 'c']
+      })
+
+      {
+        const content = await Help.run()
+        t.match(content.trim(), /Invalid command:/)
+        t.match(content, /\$ command\.spec get c/)
+      }
+    })
   })
 
   // internal argv parsing