stream-limit-throughput/create-drain.js

Advanced throughput throttling for node streams

'use strict';

exports.__esModule = true;
exports.createTf = exports.drainTransform = undefined;

var _through = require('through2');

var _through2 = _interopRequireDefault(_through);

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

const drainTransform = exports.drainTransform = (ts, context, chunk, cb) => {
  ts.push(chunk);
  const items = context.items -= 1; // eslint-disable-line
  if (items === 0 || items <= Math.floor(context.max / 2)) {
    if (items === 0) context.emit('drained');
    if (context.input.isPaused()) {
      context.input.resume();
      context.emit('filling');
    }
  }
  cb();
};

const createTf = exports.createTf = context => function tf(chunk, enc, cb) {
  return drainTransform(this, context, chunk, cb);
};

exports['default'] = context => (0, _through2['default'])({ objectMode: context.objectMode }, createTf(context));