diff --git a/docs/api/config.md b/docs/api/config.md
index 87eec15fb..b5b72e022 100644
--- a/docs/api/config.md
+++ b/docs/api/config.md
@@ -6,7 +6,7 @@ Vue Test Utils includes a config object to defined options used by Vue Test Util
 
 ### `stubs`
 
-- type: `Object`
+- type: `{ [name: string]: Component | boolean | string }`
 - default: `{
   transition: TransitionStub,
   'transition-group': TransitionGroupStub
@@ -46,7 +46,7 @@ VueTestUtils.config.mocks['$store'] = {
 
 ### `methods`
 
-- type: `Object`
+- type: `{ [name: string]: Function }`
 - default: `{}`
 
 You can configure default methods using the `config` object. This can be useful for plugins that inject methods to components, like [VeeValidate](https://vee-validate.logaretm.com/). You can override methods set in `config` by passing `methods` in the mounting options.
diff --git a/flow/config.flow.js b/flow/config.flow.js
new file mode 100644
index 000000000..c94e79325
--- /dev/null
+++ b/flow/config.flow.js
@@ -0,0 +1,8 @@
+declare type Config = {
+  stubs?: { [name: string]: Component | boolean | string },
+  mocks?: Object,
+  methods?: { [name: string]: Function },
+  provide?: Object,
+  logModifiedComponents?: boolean,
+  silent?: boolean
+};
diff --git a/flow/options.flow.js b/flow/options.flow.js
index 9765cd612..e88ddc9c6 100644
--- a/flow/options.flow.js
+++ b/flow/options.flow.js
@@ -3,15 +3,15 @@ declare type Options = {
   attachToDocument?: boolean,
   propsData?: Object,
   mocks?: Object,
-  methods?: Object,
+  methods?: { [key: string]: Function },
   slots?: SlotsObject,
-  scopedSlots?: Object,
+  scopedSlots?: { [key: string]: string },
   localVue?: Component,
   provide?: Object,
-  stubs?: Object,
+  stubs?: Stubs,
   context?: Object,
-  attrs?: Object,
-  listeners?: Object,
+  attrs?: { [key: string]: string },
+  listeners?: { [key: string]: Function | Array<Function> },
   logModifiedComponents?: boolean,
   sync?: boolean
 };
@@ -19,3 +19,7 @@ declare type Options = {
 declare type SlotValue = Component | string | Array<Component | string>;
 
 declare type SlotsObject = { [name: string]: SlotValue };
+
+declare type Stubs = {
+  [name: string]: Component | true | string
+} | Array<string>
diff --git a/flow/wrapper.flow.js b/flow/wrapper.flow.js
index 75a22fe0a..e677685a9 100644
--- a/flow/wrapper.flow.js
+++ b/flow/wrapper.flow.js
@@ -4,6 +4,7 @@ import type Wrapper from '~src/Wrapper'
 import type WrapperArray from '~src/WrapperArray'
 
 declare type Selector = any;
+declare type Components = { [name: string]: Component };
 
 declare interface BaseWrapper {
   // eslint-disable-line no-undef
diff --git a/packages/shared/merge-options.js b/packages/shared/merge-options.js
index 9bdb58977..9d9fd9bc4 100644
--- a/packages/shared/merge-options.js
+++ b/packages/shared/merge-options.js
@@ -1,30 +1,34 @@
 // @flow
 
-function getOptions (key, options, config) {
-  if (options || (config[key] && Object.keys(config[key]).length > 0)) {
-    if (options instanceof Function) {
-      return options
-    } else if (Array.isArray(options)) {
-      return [...options, ...Object.keys(config[key] || {})]
-    } else if (!(config[key] instanceof Function)) {
+function getOption (option, config?: Object): any {
+  if (option || (config && Object.keys(config).length > 0)) {
+    if (option instanceof Function) {
+      return option
+    } else if (Array.isArray(option)) {
+      return [...option, ...Object.keys(config || {})]
+    } else if (config instanceof Function) {
+      throw new Error(`Config can't be a Function.`)
+    } else {
       return {
-        ...config[key],
-        ...options
+        ...config,
+        ...option
       }
-    } else {
-      throw new Error(`Config can't be a Function.`)
     }
   }
 }
 
-export function mergeOptions (options: Options, config: Options): Options {
+export function mergeOptions (options: Options, config: Config): Options {
+  const mocks = (getOption(options.mocks, config.mocks): Object)
+  const methods = (
+    (getOption(options.methods, config.methods)): { [key: string]: Function })
+  const provide = ((getOption(options.provide, config.provide)): Object)
   return {
     ...options,
     logModifiedComponents: config.logModifiedComponents,
-    stubs: getOptions('stubs', options.stubs, config),
-    mocks: getOptions('mocks', options.mocks, config),
-    methods: getOptions('methods', options.methods, config),
-    provide: getOptions('provide', options.provide, config),
+    stubs: getOption(options.stubs, config.stubs),
+    mocks,
+    methods,
+    provide,
     sync: !!(options.sync || options.sync === undefined)
   }
 }
diff --git a/packages/shared/stub-components.js b/packages/shared/stub-components.js
index 57220755b..dd526cde8 100644
--- a/packages/shared/stub-components.js
+++ b/packages/shared/stub-components.js
@@ -14,11 +14,11 @@ import {
 } from './validators'
 import { compileTemplate } from './compile-template'
 
-function isVueComponent (comp) {
+function isVueComponent (comp): boolean {
   return comp && (comp.render || comp.template || comp.options)
 }
 
-function isValidStub (stub: any) {
+function isValidStub (stub: any): boolean {
   return (
     (!!stub && typeof stub === 'string') ||
     stub === true ||
@@ -26,7 +26,7 @@ function isValidStub (stub: any) {
   )
 }
 
-function resolveComponent (obj, component) {
+function resolveComponent (obj: Object, component: string): Object {
   return obj[component] ||
     obj[hyphenate(component)] ||
     obj[camelize(component)] ||
@@ -35,7 +35,7 @@ function resolveComponent (obj, component) {
     {}
 }
 
-function isRequiredComponent (name) {
+function isRequiredComponent (name): boolean {
   return (
     name === 'KeepAlive' || name === 'Transition' || name === 'TransitionGroup'
   )
@@ -59,11 +59,12 @@ function getCoreProperties (componentOptions: Component): Object {
     functional: componentOptions.functional
   }
 }
+
 function createStubFromString (
   templateString: string,
   originalComponent: Component,
   name: string
-): Object {
+): Component {
   if (!compileToFunctions) {
     throwError(
       `vueTemplateCompiler is undefined, you must pass ` +
@@ -86,7 +87,10 @@ function createStubFromString (
   }
 }
 
-function createBlankStub (originalComponent: Component, name: string) {
+function createBlankStub (
+  originalComponent: Component,
+  name: string
+): Component {
   const componentOptions = typeof originalComponent === 'function'
     ? originalComponent.extendOptions
     : originalComponent
@@ -107,8 +111,8 @@ function createBlankStub (originalComponent: Component, name: string) {
 
 export function createComponentStubs (
   originalComponents: Object = {},
-  stubs: Object
-): Object {
+  stubs: Stubs
+): Components {
   const components = {}
   if (!stubs) {
     return components
@@ -127,42 +131,47 @@ export function createComponentStubs (
       components[stub] = createBlankStub(component, stub)
     })
   } else {
-    Object.keys(stubs).forEach(stub => {
-      if (stubs[stub] === false) {
+    const stubsObject = (stubs: { [name: string]: Component | string | true })
+    Object.keys(stubsObject).forEach(stubName => {
+      const stub = stubsObject[stubName]
+      if (stub === false) {
         return
       }
-      if (!isValidStub(stubs[stub])) {
+
+      if (!isValidStub(stub)) {
         throwError(
           `options.stub values must be passed a string or ` + `component`
         )
       }
-      if (stubs[stub] === true) {
-        const component = resolveComponent(originalComponents, stub)
-        components[stub] = createBlankStub(component, stub)
+
+      if (stub === true) {
+        const component = resolveComponent(originalComponents, stubName)
+        components[stubName] = createBlankStub(component, stubName)
         return
       }
 
-      if (componentNeedsCompiling(stubs[stub])) {
-        compileTemplate(stubs[stub])
+      if (typeof stub !== 'string' && componentNeedsCompiling(stub)) {
+        compileTemplate(stub)
       }
 
-      if (originalComponents[stub]) {
+      if (originalComponents[stubName]) {
         // Remove cached constructor
-        delete originalComponents[stub]._Ctor
-        if (typeof stubs[stub] === 'string') {
-          components[stub] = createStubFromString(
-            stubs[stub],
-            originalComponents[stub],
-            stub
+        delete originalComponents[stubName]._Ctor
+        if (typeof stub === 'string') {
+          components[stubName] = createStubFromString(
+            stub,
+            originalComponents[stubName],
+            stubName
           )
         } else {
-          components[stub] = {
-            ...stubs[stub],
-            name: originalComponents[stub].name
+          const stubObject = (stub: Object)
+          components[stubName] = {
+            ...stubObject,
+            name: originalComponents[stubName].name
           }
         }
       } else {
-        if (typeof stubs[stub] === 'string') {
+        if (typeof stub === 'string') {
           if (!compileToFunctions) {
             throwError(
               `vueTemplateCompiler is undefined, you must pass ` +
@@ -170,12 +179,13 @@ export function createComponentStubs (
                 `undefined`
             )
           }
-          components[stub] = {
-            ...compileToFunctions(stubs[stub])
+          components[stubName] = {
+            ...compileToFunctions(stub)
           }
         } else {
-          components[stub] = {
-            ...stubs[stub]
+          const stubObject = (stub: Object)
+          components[stubName] = {
+            ...stubObject
           }
         }
       }
@@ -184,7 +194,10 @@ export function createComponentStubs (
   return components
 }
 
-function stubComponents (components: Object, stubbedComponents: Object) {
+function stubComponents (
+  components: Components,
+  stubbedComponents: Components
+): void {
   Object.keys(components).forEach(component => {
     const cmp = components[component]
     const componentOptions = typeof cmp === 'function'
@@ -199,7 +212,7 @@ function stubComponents (components: Object, stubbedComponents: Object) {
   })
 }
 
-export function createComponentStubsForAll (component: Component): Object {
+export function createComponentStubsForAll (component: Component): Components {
   const stubbedComponents = {}
 
   if (component.components) {
@@ -225,7 +238,9 @@ export function createComponentStubsForAll (component: Component): Object {
   return stubbedComponents
 }
 
-export function createComponentStubsForGlobals (instance: Component): Object {
+export function createComponentStubsForGlobals (
+  instance: Component
+): Components {
   const components = {}
   Object.keys(instance.options.components).forEach(c => {
     if (isRequiredComponent(c)) {
diff --git a/packages/test-utils/src/wrapper.js b/packages/test-utils/src/wrapper.js
index 53d822d69..d77ab40ac 100644
--- a/packages/test-utils/src/wrapper.js
+++ b/packages/test-utils/src/wrapper.js
@@ -76,7 +76,7 @@ export default class Wrapper implements BaseWrapper {
     )
   }
 
-  at () {
+  at (): void {
     throwError('at() must be called on a WrapperArray')
   }
 
@@ -122,7 +122,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Checks if wrapper contains provided selector.
    */
-  contains (selector: Selector) {
+  contains (selector: Selector): boolean {
     const selectorType = getSelectorTypeOrThrow(selector, 'contains')
     const nodes = findAll(this.vm, this.vnode, this.element, selector)
     const is = selectorType === REF_SELECTOR ? false : this.is(selector)
@@ -132,7 +132,9 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Returns an object containing custom events emitted by the Wrapper vm
    */
-  emitted (event?: string) {
+  emitted (
+    event?: string
+  ): Array<Array<any>> | { [name: string]: Array<Array<any>> } {
     if (!this._emitted && !this.vm) {
       throwError(`wrapper.emitted() can only be called on a Vue instance`)
     }
@@ -145,7 +147,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Returns an Array containing custom events emitted by the Wrapper vm
    */
-  emittedByOrder () {
+  emittedByOrder (): Array<{ name: string, args: Array<any> }> {
     if (!this._emittedByOrder && !this.vm) {
       throwError(
         `wrapper.emittedByOrder() can only be called on a Vue instance`
@@ -195,7 +197,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Checks if wrapper has an attribute with matching value
    */
-  hasAttribute (attribute: string, value: string) {
+  hasAttribute (attribute: string, value: string): boolean {
     warn(
       `hasAttribute() has been deprecated and will be ` +
       `removed in version 1.0.0. Use attributes() ` +
@@ -220,7 +222,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Asserts wrapper has a class name
    */
-  hasClass (className: string) {
+  hasClass (className: string): boolean {
     warn(
       `hasClass() has been deprecated and will be removed ` +
       `in version 1.0.0. Use classes() ` +
@@ -247,7 +249,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Asserts wrapper has a prop name
    */
-  hasProp (prop: string, value: string) {
+  hasProp (prop: string, value: string): boolean {
     warn(
       `hasProp() has been deprecated and will be removed ` +
       `in version 1.0.0. Use props() ` +
@@ -278,7 +280,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Checks if wrapper has a style with value
    */
-  hasStyle (style: string, value: string) {
+  hasStyle (style: string, value: string): boolean {
     warn(
       `hasStyle() has been deprecated and will be removed ` +
       `in version 1.0.0. Use wrapper.element.style ` +
@@ -494,7 +496,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Sets vm data
    */
-  setData (data: Object) {
+  setData (data: Object): void {
     if (this.isFunctionalComponent) {
       throwError(
         `wrapper.setData() cannot be called on a functional ` +
@@ -535,7 +537,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Sets vm computed
    */
-  setComputed (computed: Object) {
+  setComputed (computed: Object): void {
     if (!this.isVueInstance()) {
       throwError(
         `wrapper.setComputed() can only be called on a Vue ` +
@@ -608,7 +610,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Sets vm methods
    */
-  setMethods (methods: Object) {
+  setMethods (methods: Object): void {
     if (!this.isVueInstance()) {
       throwError(
         `wrapper.setMethods() can only be called on a Vue ` +
@@ -631,7 +633,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Sets vm props
    */
-  setProps (data: Object) {
+  setProps (data: Object): void {
     const originalConfig = Vue.config.silent
     Vue.config.silent = config.silent
     if (this.isFunctionalComponent) {
@@ -678,7 +680,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Sets element value and triggers input event
    */
-  setValue (value: any) {
+  setValue (value: any): void {
     const tagName = this.element.tagName
     const type = this.attributes().type
 
@@ -711,7 +713,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Checks radio button or checkbox element
    */
-  setChecked (checked: boolean = true) {
+  setChecked (checked: boolean = true): void {
     if (typeof checked !== 'boolean') {
       throwError('wrapper.setChecked() must be passed a boolean')
     }
@@ -761,7 +763,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Selects <option></option> element
    */
-  setSelected () {
+  setSelected (): void {
     const tagName = this.element.tagName
     const type = this.attributes().type
 
@@ -815,7 +817,7 @@ export default class Wrapper implements BaseWrapper {
   /**
    * Calls destroy on vm
    */
-  destroy () {
+  destroy (): void {
     if (!this.isVueInstance()) {
       throwError(`wrapper.destroy() can only be called on a Vue instance`)
     }
@@ -899,7 +901,7 @@ export default class Wrapper implements BaseWrapper {
     }
   }
 
-  update () {
+  update (): void {
     warn(
       `update has been removed from vue-test-utils. All ` +
         `updates are now synchronous by default`
diff --git a/packages/test-utils/types/index.d.ts b/packages/test-utils/types/index.d.ts
index 87b0cec66..7ca0fd7a7 100644
--- a/packages/test-utils/types/index.d.ts
+++ b/packages/test-utils/types/index.d.ts
@@ -141,7 +141,7 @@ type ShallowMountOptions<V extends Vue> = MountOptions<V>
 type ThisTypedShallowMountOptions<V extends Vue> = ShallowMountOptions<V> & ThisType<V>
 
 interface VueTestUtilsConfigOptions {
-  stubs?: Stubs
+  stubs?: Record<string, Component | boolean | string>
   mocks?: object
   methods?: Record<string, Function>
   provide?: object,
diff --git a/packages/test-utils/types/test/mount.ts b/packages/test-utils/types/test/mount.ts
index f085f9e59..cb847a483 100644
--- a/packages/test-utils/types/test/mount.ts
+++ b/packages/test-utils/types/test/mount.ts
@@ -75,7 +75,6 @@ mount(ClassComponent, {
 /**
  * Test for config
  */
-config.stubs = ['a']
 config.stubs = {
   foo: normalOptions,
   bar: functionalOptions,