readable-stream/lib/internal/streams/from.js

'use strict';

function asyncGeneratorStep(gen, resolve, reject, _next, _throw, key, arg) { try { var info = gen[key](arg); var value = info.value; } catch (error) { reject(error); return; } if (info.done) { resolve(value); } else { Promise.resolve(value).then(_next, _throw); } }

function _asyncToGenerator(fn) { return function () { var self = this, args = arguments; return new Promise(function (resolve, reject) { var gen = fn.apply(self, args); function _next(value) { asyncGeneratorStep(gen, resolve, reject, _next, _throw, "next", value); } function _throw(err) { asyncGeneratorStep(gen, resolve, reject, _next, _throw, "throw", err); } _next(undefined); }); }; }

function ownKeys(object, enumerableOnly) { var keys = Object.keys(object); if (Object.getOwnPropertySymbols) { var symbols = Object.getOwnPropertySymbols(object); if (enumerableOnly) symbols = symbols.filter(function (sym) { return Object.getOwnPropertyDescriptor(object, sym).enumerable; }); keys.push.apply(keys, symbols); } return keys; }

function _objectSpread(target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i] != null ? arguments[i] : {}; if (i % 2) { ownKeys(Object(source), true).forEach(function (key) { _defineProperty(target, key, source[key]); }); } else if (Object.getOwnPropertyDescriptors) { Object.defineProperties(target, Object.getOwnPropertyDescriptors(source)); } else { ownKeys(Object(source)).forEach(function (key) { Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key)); }); } } return target; }

function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }

var ERR_INVALID_ARG_TYPE = require('../../../errors').codes.ERR_INVALID_ARG_TYPE;

function from(Readable, iterable, opts) {
  var iterator;

  if (iterable && typeof iterable.next === 'function') {
    iterator = iterable;
  } else if (iterable && iterable[Symbol.asyncIterator]) iterator = iterable[Symbol.asyncIterator]();else if (iterable && iterable[Symbol.iterator]) iterator = iterable[Symbol.iterator]();else throw new ERR_INVALID_ARG_TYPE('iterable', ['Iterable'], iterable);

  var readable = new Readable(_objectSpread({
    objectMode: true
  }, opts)); // Reading boolean to protect against _read
  // being called before last iteration completion.

  var reading = false;

  readable._read = function () {
    if (!reading) {
      reading = true;
      next();
    }
  };

  function next() {
    return _next2.apply(this, arguments);
  }

  function _next2() {
    _next2 = _asyncToGenerator(function* () {
      try {
        var _ref = yield iterator.next(),
            value = _ref.value,
            done = _ref.done;

        if (done) {
          readable.push(null);
        } else if (readable.push((yield value))) {
          next();
        } else {
          reading = false;
        }
      } catch (err) {
        readable.destroy(err);
      }
    });
    return _next2.apply(this, arguments);
  }

  return readable;
}

module.exports = from;