stream-bootstrap

A stream which wires itself up based on the first data it receives. Aka building an airplaine while it's flying.

Installation

This module is installed via npm:

$ npm install stream-bootstrap

Example Usage

var streamify = require('stream-array');
var through = require('through2').obj;
var stdout = require('stdout');
 
var bootstrap = require('stream-bootstrap');
 
var boostrapper = bootstrap(function (chunk, enc, cb) {
  if (chunk === '+') {
    var total = 0;
    return cb(null, through(function(chunk, enc, cb) {
      total += chunk;
      this.push(total);
      cb();
    });
  } else if (chunk === '*') {
    var product = 0;
    return cb(null, through(function(chunk, enc, cb) {
      product *= chunk
      this.push(product);
      cb();
    });
  }
});
 
streamify(['+', 1, 2, 3, 4]).pipe(bootstraper).pipe(stdout());
//=> 1 3 6 10
 
streamify(['*', 1, 2, 3, 4]).pipe(bootstraper).pipe(stdout());
//=> 1 2 6 24

Retaining the first chunk

streamify(['keep']).pipe(bootstrap(function(chunk, enc, cb) {
  var stream = ...;
 
  stream.write(chunk);
 
  cb(null, stream);
}))