编写 koa 异步函数中间件时出错
Error composing koa async function middleware
我正在使用 koa-compose
按照 guide 中的建议将中间件放在一起。我将 koa-compose
导入为 kompose
.
我有以下代码:
const home = async function home (ctx,next) {
if(ctx.path === '/') {
ctx.body = 'Hello World!'
} else {
await next()
}
}
const random = async function random (ctx,next) {
console.log(ctx)
if(ctx.path === '/random') {
console.log('Inside random function')
ctx.body = Math.floor(Math.random() * 10)
} else {
await next()
}
}
const backwards = async function backwards (ctx,next) {
if(ctx.path === '/backwards') {
ctx.body = 'sdrawkcab'
} else {
await next()
}
}
const pi = async function pi (ctx,next) {
if(ctx.path === '/pi') {
ctx.body = String(Math.PI)
} else {
await next()
}
}
const body2 = kompose([random,backwards,pi,home])
我用它作为链中的最后一个中间件:
app.use(responseTime())
app.use(logger())
app.use(body2)
app.listen(3000)
我收到这个错误:
TypeError: undefined is not a function
at Object.<anonymous> (/home/vamsi/Do/koa-tutorial/node_modules/koa-compose/index.js:28:19)
at undefined.next (native)
at onFulfilled (/home/vamsi/Do/koa-tutorial/node_modules/co/index.js:65:19)
at /home/vamsi/Do/koa-tutorial/node_modules/co/index.js:54:5
at new Promise (/home/vamsi/.nvm/v6.2.0/lib/node_modules/babel-cli/node_modules/core-js/modules/es6.promise.js:191:7)
at Object.co (/home/vamsi/Do/koa-tutorial/node_modules/co/index.js:50:10)
at converted (/home/vamsi/Do/koa-tutorial/node_modules/koa-convert/index.js:17:15)
at dispatch (/home/vamsi/Do/koa-tutorial/node_modules/koa/node_modules/koa-compose/index.js:43:32)
at next (/home/vamsi/Do/koa-tutorial/node_modules/koa/node_modules/koa-compose/index.js:44:18)
at _callee7$ (index.js:72:11)
完整代码为。您可以在此处的代码中将 body()
替换为 body2
。
更新:
在做了一些额外的日志记录之后,它说:
TypeError: next is not a function
at Object._callee3$ (index.js:29:11)
at tryCatch (/home/vamsi/.nvm/v6.2.0/lib/node_modules/babel-cli/node_modules/regenerator-runtime/runtime.js:62:40)
at GeneratorFunctionPrototype.invoke [as _invoke] (/home/vamsi/.nvm/v6.2.0/lib/node_modules/babel-cli/node_modules/regenerator-runtime/runtime.js:336:22)
at GeneratorFunctionPrototype.prototype.(anonymous function) [as next] (/home/vamsi/.nvm/v6.2.0/lib/node_modules/babel-cli/node_modules/regenerator-runtime/runtime.js:95:21)
at step (index.js:3:1)
at index.js:3:1
at new Promise (/home/vamsi/.nvm/v6.2.0/lib/node_modules/babel-cli/node_modules/core-js/modules/es6.promise.js:191:7)
at Object.<anonymous> (index.js:3:1)
at Object.backwards (index.js:25:7)
at Object.<anonymous> (/home/vamsi/Do/koa-tutorial/node_modules/koa-compose/index.js:25:28),
您正在为 Koa 2 使用基于生成器的 koa-compose
,这将不起作用。您需要 koa-compose@3.x
安装:
npm install -S koa-compose@next
我正在使用 koa-compose
按照 guide 中的建议将中间件放在一起。我将 koa-compose
导入为 kompose
.
我有以下代码:
const home = async function home (ctx,next) {
if(ctx.path === '/') {
ctx.body = 'Hello World!'
} else {
await next()
}
}
const random = async function random (ctx,next) {
console.log(ctx)
if(ctx.path === '/random') {
console.log('Inside random function')
ctx.body = Math.floor(Math.random() * 10)
} else {
await next()
}
}
const backwards = async function backwards (ctx,next) {
if(ctx.path === '/backwards') {
ctx.body = 'sdrawkcab'
} else {
await next()
}
}
const pi = async function pi (ctx,next) {
if(ctx.path === '/pi') {
ctx.body = String(Math.PI)
} else {
await next()
}
}
const body2 = kompose([random,backwards,pi,home])
我用它作为链中的最后一个中间件:
app.use(responseTime())
app.use(logger())
app.use(body2)
app.listen(3000)
我收到这个错误:
TypeError: undefined is not a function
at Object.<anonymous> (/home/vamsi/Do/koa-tutorial/node_modules/koa-compose/index.js:28:19)
at undefined.next (native)
at onFulfilled (/home/vamsi/Do/koa-tutorial/node_modules/co/index.js:65:19)
at /home/vamsi/Do/koa-tutorial/node_modules/co/index.js:54:5
at new Promise (/home/vamsi/.nvm/v6.2.0/lib/node_modules/babel-cli/node_modules/core-js/modules/es6.promise.js:191:7)
at Object.co (/home/vamsi/Do/koa-tutorial/node_modules/co/index.js:50:10)
at converted (/home/vamsi/Do/koa-tutorial/node_modules/koa-convert/index.js:17:15)
at dispatch (/home/vamsi/Do/koa-tutorial/node_modules/koa/node_modules/koa-compose/index.js:43:32)
at next (/home/vamsi/Do/koa-tutorial/node_modules/koa/node_modules/koa-compose/index.js:44:18)
at _callee7$ (index.js:72:11)
完整代码为body()
替换为 body2
。
更新:
在做了一些额外的日志记录之后,它说:
TypeError: next is not a function
at Object._callee3$ (index.js:29:11)
at tryCatch (/home/vamsi/.nvm/v6.2.0/lib/node_modules/babel-cli/node_modules/regenerator-runtime/runtime.js:62:40)
at GeneratorFunctionPrototype.invoke [as _invoke] (/home/vamsi/.nvm/v6.2.0/lib/node_modules/babel-cli/node_modules/regenerator-runtime/runtime.js:336:22)
at GeneratorFunctionPrototype.prototype.(anonymous function) [as next] (/home/vamsi/.nvm/v6.2.0/lib/node_modules/babel-cli/node_modules/regenerator-runtime/runtime.js:95:21)
at step (index.js:3:1)
at index.js:3:1
at new Promise (/home/vamsi/.nvm/v6.2.0/lib/node_modules/babel-cli/node_modules/core-js/modules/es6.promise.js:191:7)
at Object.<anonymous> (index.js:3:1)
at Object.backwards (index.js:25:7)
at Object.<anonymous> (/home/vamsi/Do/koa-tutorial/node_modules/koa-compose/index.js:25:28),
您正在为 Koa 2 使用基于生成器的 koa-compose
,这将不起作用。您需要 koa-compose@3.x
安装:
npm install -S koa-compose@next