Update metadata

node_modules/yargs/lib/middleware.js

@@ -1,10 +1,65 @@
-module.exports = function (globalMiddleware, context) {
-  return function (callback) {
+'use strict'
+
+// hoisted due to circular dependency on command.
+module.exports = {
+  applyMiddleware,
+  commandMiddlewareFactory,
+  globalMiddlewareFactory
+}
+const isPromise = require('./is-promise')
+const argsert = require('./argsert')
+
+function globalMiddlewareFactory (globalMiddleware, context) {
+  return function (callback, applyBeforeValidation = false) {
+    argsert('<array|function> [boolean]', [callback, applyBeforeValidation], arguments.length)
     if (Array.isArray(callback)) {
+      for (let i = 0; i < callback.length; i++) {
+        if (typeof callback[i] !== 'function') {
+          throw Error('middleware must be a function')
+        }
+        callback[i].applyBeforeValidation = applyBeforeValidation
+      }
       Array.prototype.push.apply(globalMiddleware, callback)
     } else if (typeof callback === 'function') {
+      callback.applyBeforeValidation = applyBeforeValidation
       globalMiddleware.push(callback)
     }
     return context
   }
 }
+
+function commandMiddlewareFactory (commandMiddleware) {
+  if (!commandMiddleware) return []
+  return commandMiddleware.map(middleware => {
+    middleware.applyBeforeValidation = false
+    return middleware
+  })
+}
+
+function applyMiddleware (argv, yargs, middlewares, beforeValidation) {
+  const beforeValidationError = new Error('middleware cannot return a promise when applyBeforeValidation is true')
+  return middlewares
+    .reduce((accumulation, middleware) => {
+      if (middleware.applyBeforeValidation !== beforeValidation &&
+          !isPromise(accumulation)) {
+        return accumulation
+      }
+
+      if (isPromise(accumulation)) {
+        return accumulation
+          .then(initialObj =>
+            Promise.all([initialObj, middleware(initialObj, yargs)])
+          )
+          .then(([initialObj, middlewareObj]) =>
+            Object.assign(initialObj, middlewareObj)
+          )
+      } else {
+        const result = middleware(argv, yargs)
+        if (beforeValidation && isPromise(result)) throw beforeValidationError
+
+        return isPromise(result)
+          ? result.then(middlewareObj => Object.assign(accumulation, middlewareObj))
+          : Object.assign(accumulation, result)
+      }
+    }, argv)
+}