data: {
  child: {
    key: value
  }
}

const getDataDefinition = function (data, properties) {
  const ret = {}
  Object.keys(data).forEach((key) => {
    ret[key] = data[key]
  })
  if (properties) {
    Object.keys(properties).forEach((key) => {
      let value = null
      const def = properties[key]
      const typeIndex = TYPES.indexOf(def)
      if (typeIndex >= 0) {
        value = TYPE_DEFAULT_VALUES[typeIndex]
      } else if (def.value) {
        value = def.value
      } else {
        const typeIndex = TYPES.indexOf(def.type)
        if (typeIndex >= 0) {
          value = TYPE_DEFAULT_VALUES[typeIndex]
        }
      }
      ret[key] = value
    })
  }
  return ret
}

VM2638:1 thirdScriptError 
 sdk uncaught third Error 
 module "components/pullup/miniprogram-computed" is not defined 
 Error: module "components/pullup/miniprogram-computed" is not defined

const computedBehavior = require('miniprogram-computed');
const testBehavior = require('./test.behavior');


Component({
  behaviors: [testBehavior, computedBehavior],
  data: {

  },
  computed: {
    c(data) {
      return data.a + data.b;
    }
  },
  methods: {
  }
})

module.exports = Behavior({
  data: {
    a: 1,
    b: 2
  }
})

export const store = observable({

  // 数据字段
  numA: 4,
  numB: 5,
  accounts: [4, 5, 6],

  add: action(function() {
    this.accounts = [1, 2, 3]
  }),

  // actions
  update: action(function () {
    this.numA = this.numA + 1
    this.numB = this.numA + 1
  })

})

VM824:1 MiniProgramError
data.accounts.reduce is not a function
TypeError: data.accounts.reduce is not a function
    at sum (http://127.0.0.1:63254/appservice/index/components/computed-example.js:17:28)
    at http://127.0.0.1:63254/appservice/components/index.js:392:21
    at Array.forEach (<anonymous>)
    at Ge.created (http://127.0.0.1:63254/appservice/components/index.js:385:34)
    at r.safeCallback (http://127.0.0.1:63254/appservice/__dev__/WAService.js:2:1775504)
    at r.call (http://127.0.0.1:63254/appservice/__dev__/WAService.js:2:1775397)
    at Function.M._advancedCreate (http://127.0.0.1:63254/appservice/__dev__/WAService.js:2:1823182)
    at r.createComponent (http://127.0.0.1:63254/appservice/__dev__/WAService.js:2:1834383)
    at e (http://127.0.0.1:63254/appservice/__dev__/WAService.js:2:1919566)
    at e (http://127.0.0.1:63254/appservice/__dev__/WAService.js:2:1920093)

Component({
  behaviors: [behaviorTest, storeBindingsBehavior, computedBehavior],
  computed: {
    sum(data) {
      console.log(data.accounts)
      return data.accounts.reduce((s, o) => s + o, 0)
    },
  },
  data: {
    a: 1,
    b: 1,
  },
  storeBindings: {
    store,
    fields: ['numA', 'numB','accounts'],
    actions: {
      buttonTap: 'add'
    },
  },

  methods: {
    onTap() {
      console.log(this.data.accounts[0], this.data.accounts.reduce((s, o) => s + o, 0))
      this.buttonTap()
    }
  }
})

// 计算 computed
const calcComputed = function () {
    const data = this.data = this.data || {}
    const computed = data._computed || {}
    const computedKeys = Object.keys(computed)
    const needUpdate = {}

    for (let i = 0, len = computedKeys.length; i < len; i++) {
        const key = computedKeys[i]
        const getter = computed[key]

        if (typeof getter === 'function') {
            const value = getter.call(this)

            this._computedCache = this._computedCache || {}
            if (this._computedCache[key] !== value) {
                needUpdate[key] = value
                this._computedCache[key] = value
            }
        }
    }

    return needUpdate
}

module.exports = Behavior({
    lifetimes: {
        attached() {
            this._originalSetData = this.setData
            this.setData = this._setData
            this.setData({})
        }
    },
    definitionFilter(defFields) {
        const computed = defFields.computed || {}

        defFields.data = defFields.data || {}
        defFields.data._computed = computed

        defFields.methods = defFields.methods || {}
        defFields.methods._setData = function (data, callback) {
            const originalSetData = this._originalSetData

            if (this._doingSetData) {
                // eslint-disable-next-line no-console
                console.warn('can\'t call setData in computed getter function!')
                return
            }

            this._doingSetData = true

            // TODO 过滤掉 data 中的 computed 字段
            const dataKeys = Object.keys(data)
            for (let i = 0, len = dataKeys.length; i < len; i++) {
                const key = dataKeys[i]

                if (computed[key]) delete data[key]
            }

            // 做 data 属性的 setData
            originalSetData.call(this, data, callback)

            // 计算 computed
            const needUpdate = calcComputed.call(this)

            // 做 computed 属性的 setData
            originalSetData.call(this, needUpdate)

            this._doingSetData = false
        }
    }
})