正式版计划支持的写法

[WendaoLee]

Goal.Example

import {TMap} from 'Base'

let map = TMap.Map("domId") // it will create thunk,but map reffer to a reference of thunk and it will auto become instance or value after thunk has been evaluated.
let center = TMap.LatLng(120,31)
map.setCenter(center) //thunk can create new thunk,and can receive thunks

[WendaoLee]

也许不能直接通过thunk创建一个新thunk

[WendaoLee]

draft

// getter get a thunk which represent the return type
// new always get ThunkProxy,not thunk itself represented.
// every code with thunk do nothing in the level of coder.Writing thunk just declare caculation.And all caculation will do implicitly as orders declared.
// if user want to get thunk's result,use util function thunkRef(),and use util function isThunk() to check whether thunk has been evaluated correctly.
import {TMap} from 'Base'

let map = TMap.Map("domid") //a proxy instance of thunks.Use this as the `TMap.Map` in TencentMap.Operations on it will create Thunks.
let mapT = TMap.Map("domid").thunk() // get MapThunk
let center = map.getCenter() //get LatLngThunk,because getCenter return LatLng
let lat = center.getLat() //get NumberThunk,with LatLngThunk supporting create new thunk represented number.

mapT = thunkRef(mapT) // make mapT point to a MapThunk,which will auto becomes MapThunk's result `map` when MapThunk evaluated.

[WendaoLee]

也许不能直接通过thunk创建一个新thunk

事实上是可以的。但是问题在于thunk是否应该引入一个默认的hook来保证thunk的按序执行。按序执行还有一个问题，是否应该在错误发生时中断？

[WendaoLee]

draft.Thunk With Promise.

// for some situation e.g wait for data from server
import {TMap,LatLng} from 'Base'

let map = TMap.Map("domid")

axios.get('https://example').then((res)=>{
  data = res.data // e.g {lat:1,lng:1}
  map.setCenter(new TMap.LatLng(data.lat,data.lng).thunk()) // passing thunk into thunk.
})

let defaultCenter = new TMap.LatLng(data.lat,data.lng).thunk()
map.setCenter(defaultCenter)

//above will do as expected.As `(res)=>{}` creating thunk after `defaultCenter`

[WendaoLee]

draft.Thunk Suck

seems need thunk suck for sleeping condition.

[WendaoLee]

draft.ThunkProxy And ThunkSymbol

What is the ThunkProxy?

Every constructor function in TencentMap which can use with new operator is a ThunkProxy in cuteTencentMap. ThunkProxy is a proxy of thunk.You can use it to create new thunks represented the operation on TencentMap's related method.

e.g

import {TMap} from 'Base'
let map = new TMap.Map("domid") //it creare ThunkProxy of TMap.Map
map.getCenter() //ThunkProxy ensure the methods of TMap.Map you created invoke correctly when it being evaluated.That means the center you get is from the  `let map = TMap.Map("domid")` 's map instance.Not others. 

ThunkProxy not Thunk itself.If you want to pass arguments to a method which need type from TencentMap,you should use .thunk() to get the thunk.

e.g. TMap.Map.setCenter(latlng) need latlng to be type of TMap.LatLng

import {TMap} from 'Base'

let map = new TMap.Map("domid")
let center = new TMap.LatLng(12,3)
map.setCenter(center.thunk()) // need `.thunk()` because `new` create `ThunkProxy`,not `Thunk`

class ThunkProxy{
  target
  __type__ = "ThunkProxy"
}

class ThunkSymbol{
  __type__ = "ThunkSymbol"
}

[WendaoLee]

some method has object options.Should it be a thunk?And how to deal with these thunks?

new TMap.Map(domId, options);
//optins.center :: TMap.LatLng

note: it should not be a thunk.Just write special case of evaluate function.