ducted

The purpose of ducted is to act as a general-purpose pipeline manager. A pipeline is built from steps, each of which processes a context (synchronously or asynchronously). A step is typically either a function or itself a pipeline.

It essentially tries to hit a sweet spot not far from streams and promises, but without doing your head in and with a number of additional facilities that are useful when implementing a pipeline.

An example, even a stupid one like the following, should give you an idea.

import { pipe } from 'ducted';
import fs from 'fs';
pipe(
  ctx => fs.readFile(ctx.data.source, 'utf8', (err, content) => {
          if (err) ctx.error(err);
          ctx.content = content;
          ctx.done();
        }),
  ctx => {
          if (/unicorn/i.test(ctx.data.content)) ctx.warn('Shh, do not mention the unicorns.');
          ctx.done();
  },
  ctx => { ctx.data.content = ctx.data.content.toUpperCase(); ctx.done(); },
  ctx => fs.writeFile(ctx.data.output, ctx.data.content, 'utf8', (err) => {
            if (err) ctx.error(err);
            ctx.done();
        })
)
.on('duct:end', (data) => {
  console.log('Uppercased some data');
})
.run({ source: 'in.txt', output: 'out.txt' });

Obviously, the above example is pretty contrived. It would be a lot easier to just code it out without ducted. But ducted starts to shine in more elaborate pipelines, with more complex flows, and when code is reused and pipelines get composed.