fix: make prefixed usage errors more consistent

PR-URL: #3987
Credit: @lukekarrys
Close: #3987
Reviewed-by: @wraithgar

Author: lukekarrys

lib/base-command.js

@@ -53,14 +53,10 @@ class BaseCommand {
     return results
   }
 
-  usageError (msg) {
-    if (!msg) {
-      return Object.assign(new Error(`\nUsage: ${this.usage}`), {
-        code: 'EUSAGE',
-      })
-    }
-
-    return Object.assign(new Error(`\nUsage: ${msg}\n\n${this.usage}`), {
+  usageError (prefix = '') {
+    if (prefix)
+      prefix += '\n\n'
+    return Object.assign(new Error(`\nUsage: ${prefix}${this.usage}`), {
       code: 'EUSAGE',
     })
   }

lib/commands/cache.js

@@ -116,7 +116,7 @@ class Cache extends BaseCommand {
       case 'ls':
         return await this.ls(args)
       default:
-        throw Object.assign(new Error(this.usage), { code: 'EUSAGE' })
+        throw this.usageError()
     }
   }
 
@@ -161,14 +161,9 @@ class Cache extends BaseCommand {
   // npm cache add <tarball>...
   // npm cache add <folder>...
   async add (args) {
-    const usage = 'Usage:\n' +
-      '    npm cache add <tarball-url>...\n' +
-      '    npm cache add <pkg>@<ver>...\n' +
-      '    npm cache add <tarball>...\n' +
-      '    npm cache add <folder>...\n'
     log.silly('cache add', 'args', args)
     if (args.length === 0)
-      throw Object.assign(new Error(usage), { code: 'EUSAGE' })
+      throw this.usageError('First argument to `add` is required')
 
     return Promise.all(args.map(spec => {
       log.silly('cache add', 'spec', spec)

lib/commands/diff.js

@@ -49,12 +49,8 @@ class Diff extends BaseCommand {
 
   async exec (args) {
     const specs = this.npm.config.get('diff').filter(d => d)
-    if (specs.length > 2) {
-      throw new TypeError(
-        'Can\'t use more than two --diff arguments.\n\n' +
-        `Usage:\n${this.usage}`
-      )
-    }
+    if (specs.length > 2)
+      throw this.usageError(`Can't use more than two --diff arguments.`)
 
     // execWorkspaces may have set this already
     if (!this.prefix)
@@ -101,7 +97,7 @@ class Diff extends BaseCommand {
     }
 
     if (!name)
-      throw this.usageError('Needs multiple arguments to compare or run from a project dir.\n')
+      throw this.usageError('Needs multiple arguments to compare or run from a project dir.')
 
     return name
   }
@@ -133,7 +129,7 @@ class Diff extends BaseCommand {
       noPackageJson = true
     }
 
-    const missingPackageJson = this.usageError('Needs multiple arguments to compare or run from a project dir.\n')
+    const missingPackageJson = this.usageError('Needs multiple arguments to compare or run from a project dir.')
 
     // using a valid semver range, that means it should just diff
     // the cwd against a published version to the registry using the
@@ -222,7 +218,7 @@ class Diff extends BaseCommand {
         `file:${this.prefix}`,
       ]
     } else
-      throw this.usageError(`Spec type ${spec.type} not supported.\n`)
+      throw this.usageError(`Spec type ${spec.type} not supported.`)
   }
 
   async convertVersionsToSpecs ([a, b]) {
@@ -239,7 +235,7 @@ class Diff extends BaseCommand {
       }
 
       if (!pkgName)
-        throw this.usageError('Needs to be run from a project dir in order to diff two versions.\n')
+        throw this.usageError('Needs to be run from a project dir in order to diff two versions.')
 
       return [`${pkgName}@${a}`, `${pkgName}@${b}`]
     }

lib/commands/edit.js

@@ -35,7 +35,7 @@ class Edit extends BaseCommand {
 
   async exec (args) {
     if (args.length !== 1)
-      throw new Error(this.usage)
+      throw this.usageError()
 
     const path = splitPackageNames(args[0])
     const dir = resolve(this.npm.dir, path)

lib/commands/exec.js

@@ -80,7 +80,7 @@ class Exec extends BaseCommand {
     const yes = this.npm.config.get('yes')
 
     if (call && _args.length)
-      throw this.usage
+      throw this.usageError()
 
     return libexec({
       ...flatOptions,

lib/commands/explore.js

@@ -34,14 +34,14 @@ class Explore extends BaseCommand {
 
   async exec (args) {
     if (args.length < 1 || !args[0])
-      throw this.usage
+      throw this.usageError()
 
     const pkgname = args.shift()
 
     // detect and prevent any .. shenanigans
     const path = join(this.npm.dir, join('/', pkgname))
     if (relative(path, this.npm.dir) === '')
-      throw this.usage
+      throw this.usageError()
 
     // run as if running a script named '_explore', which we set to either
     // the set of arguments, or the shell config, and let @npmcli/run-script

lib/commands/help-search.js

@@ -28,7 +28,7 @@ class HelpSearch extends BaseCommand {
 
   async exec (args) {
     if (!args.length)
-      return this.npm.output(this.usage)
+      throw this.usageError()
 
     const docPath = path.resolve(__dirname, '..', '..', 'docs/content')
     const files = await glob(`${docPath}/*/*.md`)

lib/commands/hook.js

@@ -43,7 +43,7 @@ class Hook extends BaseCommand {
         case 'up':
           return this.update(args[1], args[2], args[3], opts)
         default:
-          throw this.usage
+          throw this.usageError()
       }
     })
   }

lib/commands/pkg.js

@@ -96,10 +96,7 @@ class Pkg extends BaseCommand {
 
   async set (args) {
     const setError = () =>
-      Object.assign(
-        new TypeError('npm pkg set expects a key=value pair of args.'),
-        { code: 'EPKGSET' }
-      )
+      this.usageError('npm pkg set expects a key=value pair of args.')
 
     if (!args.length)
       throw setError()
@@ -123,10 +120,7 @@ class Pkg extends BaseCommand {
 
   async delete (args) {
     const setError = () =>
-      Object.assign(
-        new TypeError('npm pkg delete expects key args.'),
-        { code: 'EPKGDELETE' }
-      )
+      this.usageError('npm pkg delete expects key args.')
 
     if (!args.length)
       throw setError()

lib/commands/profile.js

@@ -90,7 +90,7 @@ class Profile extends BaseCommand {
 
   async exec (args) {
     if (args.length === 0)
-      throw new Error(this.usage)
+      throw this.usageError()
 
     log.gauge.show('profile')