为什么我的同构 Cycle.js 应用程序在服务器上呈现时会导致 xstream 异常？

Question

我正在尝试编写同构演示 Cycle.js/Hapi.js app, but it fails with an exception in xstream while rendering on the server. What is going wrong here? I've based my app on Cycle.js' isomorphic app example。

追溯看起来像这样：

TypeError: Uncaught error: s[i]._add is not a function
    at CombineProducer._start (/Users/arve/Projects/hapi-cycle/node_modules/xstream/core.js:190:22)
    at Stream._add (/Users/arve/Projects/hapi-cycle/node_modules/xstream/core.js:976:19)
    at MapOperator._start (/Users/arve/Projects/hapi-cycle/node_modules/xstream/core.js:717:18)
    at Stream._add (/Users/arve/Projects/hapi-cycle/node_modules/xstream/core.js:976:19)
    at LastOperator._start (/Users/arve/Projects/hapi-cycle/node_modules/xstream/core.js:596:18)
    at Stream._add (/Users/arve/Projects/hapi-cycle/node_modules/xstream/core.js:976:19)
    at Stream.addListener (/Users/arve/Projects/hapi-cycle/node_modules/xstream/core.js:1050:14)
    at Object.streamSubscribe (/Users/arve/Projects/hapi-cycle/node_modules/@cycle/xstream-adapter/lib/index.js:39:16)
    at /Users/arve/Projects/hapi-cycle/node_modules/@cycle/base/lib/index.js:49:30
    at Array.map (native)

渲染代码基本如下所示：

import Cycle from '@cycle/xstream-run'
import xs from 'xstream'
import {html, section, h1, p, head, title, body, div, script, makeHTMLDriver,} from '@cycle/dom'
import serialize from 'serialize-javascript'
import Logger from '@arve.knudsen/js-logger'
let logger = Logger.get('server.rendering')

let wrapVTreeWithHtmlBoilerplate = ([vtree, context,]) => {
  return (
    html([
      head([
        title('Cycle Isomorphism Example'),
      ]),
      body([
        div('.app-container', [vtree,]),
        script(`window.appContext = ${serialize(context)};`),
        // script(clientBundle),
      ]),
    ])
  );
}

let main = (sources) => {
  let vtree = (
    section('.home', [
      h1('The homepage'),
      p('Welcome to our spectacular web page with nothing special here.'),
    ])
  )
  return {
    DOM: vtree,
  }
}

let renderIndex = (request, reply) => {
  let context = xs.of({})
  Cycle.run((sources) => {
    let vtree = main(sources).DOM
    let wrappedVTree = xs.combine(vtree, context)
      .map(wrapVTreeWithHtmlBoilerplate)
      .last()
    return {
      DOM: wrappedVTree,
    };
  }, {
    DOM: makeHTMLDriver((html) => {
      let wrappedHtml = `<!doctype html>${html}`
    }),
    context: () => {return context},
    PreventDefault: () => {},
  })
}

您可以找到完整的源代码 here。

我运行在 OS X 上使用 Node v6.6.0、babel-node 6.14.0、Hapi 15.0.3、@cycle/dom 12.2.5 和@cycle/xstream-run 3.1.0。如果您需要更多信息，请告诉我。

Answer 1

错误的原因是渲染的 VTree 不是流。我将代码更改为以下内容并且有效：

let vtree = sources.context.map(({}) => {
   return (
    section('.home', [
      h1('The homepage'),
      p('Welcome to our spectacular web page with nothing special here.'),
    ])
  )
})
return {
  DOM: vtree,
}

sources.context.map 调用（我从原来的同构示例中借用）确保 vtree 是一个流。

为什么我的同构 Cycle.js 应用程序在服务器上呈现时会导致 xstream 异常？

Why does my isomorphic Cycle.js app cause an xstream exception when rendering on server?

javascript

isomorphic-javascript

cyclejs

hapi.js

xstream-js