stream-limit-throughput/stream-limit-throughput.js

Advanced throughput throttling for node streams

'use strict';

exports.__esModule = true;
exports.MAX_ALLOWED_ITEMS = exports.DEFAULT_MAX_ITEMS_IN_FLIGHT = undefined;
exports['default'] = streamLimitThroughput;

var _events = require('events');

var _events2 = _interopRequireDefault(_events);

var _isStream = require('is-stream');

var _isStream2 = _interopRequireDefault(_isStream);

var _runGarbageCollection = require('./run-garbage-collection');

var _runGarbageCollection2 = _interopRequireDefault(_runGarbageCollection);

var _createFill = require('./create-fill');

var _createFill2 = _interopRequireDefault(_createFill);

var _createDrain = require('./create-drain');

var _createDrain2 = _interopRequireDefault(_createDrain);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }

const DEFAULT_MAX_ITEMS_IN_FLIGHT = exports.DEFAULT_MAX_ITEMS_IN_FLIGHT = 50;
const MAX_ALLOWED_ITEMS = exports.MAX_ALLOWED_ITEMS = 4096;

function streamLimitThroughput({ input, max, objectMode } = {}) {
  // set input stream property
  if (!(0, _isStream2['default'])(input)) throw new Error('inputStream is required');

  // context as EventEmitter
  const context = new _events2['default']();
  context.input = input;
  context.objectMode = objectMode;
  context.items = 0;
  context.max = ~~max; // eslint-disable-line no-bitwise

  if (context.max < 1 || context.max > MAX_ALLOWED_ITEMS) {
    context.max = DEFAULT_MAX_ITEMS_IN_FLIGHT;
  }

  context.fill = (0, _createFill2['default'])(context);
  context.drain = (0, _createDrain2['default'])(context);

  context.on('filling', _runGarbageCollection2['default']);

  return context;
}