app-builder

app-builder

Create composable promise based middleware pipelines.

npm install app-builder

Example

import { compose } from 'app-builder'

const app = compose([
  async function (ctx, next) {
    ctx.value += 1
    await next()
    ctx.value += 4
  },
  async function (ctx, next) {
    ctx.value += 2
    await next()
    ctx.value += 3
  }
]);

const context = { value: '' }
app(context).then(() => console.log(context.value)) // --> '1234'

Exports (3)

default - createAppBuilder() : AppBuilder

compose - Function(...middleware[] : Function[]|Function) : Function

AppBuilder - Class

---

AppBuilder#use(mw: Function) : AppBuilder

Add a middleware function to the builder. A middleware function can accept two arguments; context : any and next : Function. next must be invoked to continue the pipeline. If the middleware function returns a promise the pipeline will end only after all returned promises have been resolved.

AppBuilder#build() : Function

Get a function made up of all used middleware functions (returned function is also valid middleware)

AppBuilder Usage:

import createAppBuilder from 'app-builder'

const builder = createAppBuilder()

async function first (context, next) {
  context.value += 1
  await next()
  context.value += 4
}

async function second (context, next) {
  context.value += 2
  await next()
  context.value += 3
}

builder.use(first)
builder.use(second)

applicationFunction = builder.build()

const context = { value: '' }
applicationFunction(context).then(() => console.log(context.value)) // --> '1234'

Notes

• next() must always have a modifier, that is, it must always be awaited or yielded or returned. If it isn't, there is a strong possibility you will encounter race conditions