feat(help): refactor npm help/help-search

Lots of dead code removed thanks to streamlining of logic.
`npm help` `npm <command>` and `npm help-search` are all now separated
concerns, handling their own use cases. `help` calls `help-search` as a
last resort, but `npm <command>` no longer tries to wind its way through
to `help-search` just to get the basic npm usage displayed.

The `did you mean` output has been expanded. It now always suggests top
level commands, scripts, and bins, and suggests them in the way they
should be called.

PR-URL: https://github.com/npm/cli/pull/2859
Credit: @wraithgar
Close: #2859
Reviewed-by: @ruyadorno

1 files changed, 11 insertions, 14 deletions

diff --git a/lib/utils/npm-usage.js b/lib/utils/npm-usage.js
index b77bca7be..bc397cb4d 100644
--- a/lib/utils/npm-usage.js
+++ b/lib/utils/npm-usage.js
@@ -1,14 +1,12 @@
-const didYouMean = require('./did-you-mean.js')
 const { dirname } = require('path')
 const { cmdList } = require('./cmd-list')
 
-module.exports = (npm, valid = true) => {
-  npm.config.set('loglevel', 'silent')
+module.exports = (npm) => {
   const usesBrowser = npm.config.get('viewer') === 'browser'
     ? ' (in a browser)' : ''
-  npm.log.level = 'silent'
-  npm.output(`
-Usage: npm <command>
+  return `npm <command>
+
+Usage:
 
 npm install        install all the dependencies in your project
 npm install <foo>  add the <foo> dependency to your project
@@ -20,7 +18,7 @@ npm help <term>    search for help on <term>${usesBrowser}
 npm help npm       more involved overview${usesBrowser}
 
 All commands:
-${npm.config.get('long') ? usages(npm) : ('\n    ' + wrap(cmdList))}
+${allCommands(npm)}
 
 Specify configs in the ini-formatted file:
     ${npm.config.get('userconfig')}
@@ -29,14 +27,13 @@ or on the command line via: npm <command> --key=value
 More configuration info: npm help config
 Configuration fields: npm help 7 config
 
-npm@${npm.version} ${dirname(dirname(__dirname))}
-`)
-
-  if (npm.argv.length >= 1)
-    npm.output(didYouMean(npm.argv[0], cmdList))
+npm@${npm.version} ${dirname(dirname(__dirname))}`
+}
 
-  if (!valid)
-    process.exitCode = 1
+const allCommands = (npm) => {
+  if (npm.config.get('long'))
+    return usages(npm)
+  return ('\n    ' + wrap(cmdList))
 }
 
 const wrap = (arr) => {