ctxq

Simple promise queue with context.

Install

npm install --save ctxq

Usage

ctxq.push(key, handler)

Result of handler (wrapped in Promise.resolve) will be assigned as key in context. Returns ctxq instance for method chaining.

ctxq.push(handler)

Result of handler (wrapped in Promise.resolve) will not be assigned to context. Returns ctxq instance for method chaining.

ctxq.run(context, [catchHandler])

Runs the queue in the same order as handlers are pushed to it. Each handler will be called with context as argument. If context is a promise it will be resolved before queue is executed. This helps to chain multiple queues which should share same scope. Optional catchHandler will be executed in case of an error during queue run. It has following signature: catchHandler(err, context). Return value will be resolved. So it works exactly like a promise.catch but will be invoked with context as second argument.

Example

const CQ = require('ctxq');
 
const queue = CQ();
 
queue
    .push('user', (ctx) => db.createUser(ctx.input.user))
    .push((ctx) => email.sendMail('welcome', ctx.user))
    .push('profile', (ctx) => db.createProfileForUser(ctx.user))
    .run({ input: { user:{ /*...*/ }}})
    .then((ctx) => ctx.user)
    .then(reply, reply);

Author

@platdesign