config: Restore --dev flag, unify --omit flatteners

docs/content/using-npm/config.md

@@ -1382,6 +1382,14 @@ What authentication strategy to use with `adduser`/`login`.
 
 `--cache-min=9999 (or bigger)` is an alias for `--prefer-offline`.
 
+#### `dev`
+
+* Default: false
+* Type: Boolean
+* DEPRECATED: Please use --include=dev instead.
+
+Alias for `--include=dev`.
+
 #### `init.author.email`
 
 * Default: ""

lib/utils/config/definitions.js

@@ -22,6 +22,34 @@ const maybeReadFile = file => {
   }
 }
 
+const buildOmitList = obj => {
+  const include = obj.include || []
+  const omit = obj.omit || []
+
+  const only = obj.only
+  if (/^prod(uction)?$/.test(only) || obj.production)
+    omit.push('dev')
+
+  if (/^dev/.test(obj.also))
+    include.push('dev')
+
+  if (obj.dev)
+    include.push('dev')
+
+  if (obj.optional === false)
+    omit.push('optional')
+  else if (obj.optional === true)
+    include.push('optional')
+
+  obj.omit = [...new Set(omit)].filter(type => !include.includes(type))
+  obj.include = [...new Set(include)]
+
+  if (obj.omit.includes('dev'))
+    process.env.NODE_ENV = 'production'
+
+  return obj.omit
+}
+
 const editor = process.env.EDITOR ||
   process.env.VISUAL ||
   (isWindows ? 'notepad.exe' : 'vi')
@@ -164,12 +192,6 @@ define('also', {
   `,
   deprecated: 'Please use --include=dev instead.',
   flatten (key, obj, flatOptions) {
-    if (!/^dev(elopment)?$/.test(obj.also))
-      return
-
-    // add to include, and call the omit flattener
-    obj.include = obj.include || []
-    obj.include.push('dev')
     definitions.omit.flatten('omit', obj, flatOptions)
   },
 })
@@ -477,6 +499,18 @@ define('description', {
   },
 })
 
+define('dev', {
+  default: false,
+  type: Boolean,
+  description: `
+    Alias for \`--include=dev\`.
+  `,
+  deprecated: 'Please use --include=dev instead.',
+  flatten (key, obj, flatOptions) {
+    definitions.omit.flatten('omit', obj, flatOptions)
+  },
+})
+
 define('diff', {
   default: [],
   type: [String, Array],
@@ -1218,10 +1252,7 @@ define('omit', {
     scripts.
   `,
   flatten (key, obj, flatOptions) {
-    const include = obj.include || []
-    const omit = flatOptions.omit || []
-    flatOptions.omit = omit.concat(obj[key])
-      .filter(type => type && !include.includes(type))
+    flatOptions.omit = buildOmitList(obj)
   },
 })
 
@@ -1236,12 +1267,6 @@ define('only', {
     \`--omit=dev\`.
   `,
   flatten (key, obj, flatOptions) {
-    const value = obj[key]
-    if (!/^prod(uction)?$/.test(value))
-      return
-
-    obj.omit = obj.omit || []
-    obj.omit.push('dev')
     definitions.omit.flatten('omit', obj, flatOptions)
   },
 })
@@ -1259,16 +1284,6 @@ define('optional', {
     Alias for --include=optional or --omit=optional
   `,
   flatten (key, obj, flatOptions) {
-    const value = obj[key]
-    if (value === null)
-      return
-    else if (value === true) {
-      obj.include = obj.include || []
-      obj.include.push('optional')
-    } else {
-      obj.omit = obj.omit || []
-      obj.omit.push('optional')
-    }
     definitions.omit.flatten('omit', obj, flatOptions)
   },
 })
@@ -1385,12 +1400,6 @@ define('production', {
   deprecated: 'Use `--omit=dev` instead.',
   description: 'Alias for `--omit=dev`',
   flatten (key, obj, flatOptions) {
-    const value = obj[key]
-    if (!value)
-      return
-
-    obj.omit = obj.omit || []
-    obj.omit.push('dev')
     definitions.omit.flatten('omit', obj, flatOptions)
   },
 })