create-instance.js

// @flow

import Vue from 'vue'
import { addSlots } from './add-slots'
import { addScopedSlots } from './add-scoped-slots'
import addMocks from './add-mocks'
import addAttrs from './add-attrs'
import addListeners from './add-listeners'
import addProvide from './add-provide'
import { addEventLogger } from './log-events'
import { createComponentStubs } from 'shared/stub-components'
import { throwError, warn } from 'shared/util'
import { compileTemplate } from 'shared/compile-template'
import deleteoptions from './delete-mounting-options'
import createFunctionalComponent from './create-functional-component'
import { componentNeedsCompiling } from 'shared/validators'

function isDestructuringSlotScope (slotScope: string): boolean {
  return slotScope[0] === '{' && slotScope[slotScope.length - 1] === '}'
}

function getVueTemplateCompilerHelpers (proxy: Object): Object {
  const helpers = {}
  const names = ['_c', '_o', '_n', '_s', '_l', '_t', '_q', '_i', '_m', '_f', '_k', '_b', '_v', '_e', '_u', '_g']
  names.forEach((name) => {
    helpers[name] = proxy[name]
  })
  return helpers
}

export default function createInstance (
  component: Component,
  options: Options,
  vue: Component
): Component {
  if (options.mocks) {
    addMocks(options.mocks, vue)
  }

  if ((component.options && component.options.functional) || component.functional) {
    component = createFunctionalComponent(component, options)
  } else if (options.context) {
    throwError(
      'mount.context can only be used when mounting a functional component'
    )
  }

  if (options.provide) {
    addProvide(component, options.provide, options)
  }

  if (componentNeedsCompiling(component)) {
    compileTemplate(component)
  }

  addEventLogger(vue)

  const Constructor = vue.extend(component)

  const instanceOptions = { ...options, propsData: { ...options.propsData }}
  deleteoptions(instanceOptions)
  // $FlowIgnore
  const stubComponents = createComponentStubs(component.components, options.stubs)

  if (options.stubs) {
    instanceOptions.components = {
      ...instanceOptions.components,
      // $FlowIgnore
      ...stubComponents
    }
  }

  Object.keys(component.components || {}).forEach((c) => {
    if (component.components[c].extendOptions &&
      !instanceOptions.components[c]) {
      if (options.logModifiedComponents) {
        warn(`an extended child component ${c} has been modified to ensure it has the correct instance properties. This means it is not possible to find the component with a component selector. To find the component, you must stub it manually using the stubs mounting option.`)
      }
      instanceOptions.components[c] = vue.extend(component.components[c])
    }
  })

  Object.keys(stubComponents).forEach(c => {
    vue.component(c, stubComponents[c])
  })

  const vm = new Constructor(instanceOptions)

  // Workaround for Vue < 2.5
  vm._staticTrees = []

  addAttrs(vm, options.attrs)
  addListeners(vm, options.listeners)

  if (options.scopedSlots) {
    if (window.navigator.userAgent.match(/PhantomJS/i)) {
      throwError('the scopedSlots option does not support PhantomJS. Please use Puppeteer, or pass a component.')
    }
    const vueVersion = Number(`${Vue.version.split('.')[0]}.${Vue.version.split('.')[1]}`)
    if (vueVersion >= 2.5) {
      vm.$_vueTestUtils_scopedSlots = {}
      vm.$_vueTestUtils_slotScopes = {}
      const renderSlot = vm._renderProxy._t

      vm._renderProxy._t = function (name, feedback, props, bindObject) {
        const scopedSlotFn = vm.$_vueTestUtils_scopedSlots[name]
        const slotScope = vm.$_vueTestUtils_slotScopes[name]
        if (scopedSlotFn) {
          props = { ...bindObject, ...props }
          const helpers = getVueTemplateCompilerHelpers(vm._renderProxy)
          let proxy = { ...helpers }
          if (isDestructuringSlotScope(slotScope)) {
            proxy = { ...helpers, ...props }
          } else {
            proxy[slotScope] = props
          }
          return scopedSlotFn.call(proxy)
        } else {
          return renderSlot.call(vm._renderProxy, name, feedback, props, bindObject)
        }
      }

      // $FlowIgnore
      addScopedSlots(vm, options.scopedSlots)
    } else {
      throwError('the scopedSlots option is only supported in vue@2.5+.')
    }
  }

  if (options.slots) {
    addSlots(vm, options.slots)
  }

  return vm
}