aboutsummaryrefslogtreecommitdiff
path: root/node_modules/babel-runtime/helpers/asyncGenerator.js
blob: ebbea0964412dcc6c3a70a532b6f0536bf7e4287 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
"use strict";

exports.__esModule = true;

var _symbol = require("../core-js/symbol");

var _symbol2 = _interopRequireDefault(_symbol);

var _promise = require("../core-js/promise");

var _promise2 = _interopRequireDefault(_promise);

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

exports.default = function () {
  function AwaitValue(value) {
    this.value = value;
  }

  function AsyncGenerator(gen) {
    var front, back;

    function send(key, arg) {
      return new _promise2.default(function (resolve, reject) {
        var request = {
          key: key,
          arg: arg,
          resolve: resolve,
          reject: reject,
          next: null
        };

        if (back) {
          back = back.next = request;
        } else {
          front = back = request;
          resume(key, arg);
        }
      });
    }

    function resume(key, arg) {
      try {
        var result = gen[key](arg);
        var value = result.value;

        if (value instanceof AwaitValue) {
          _promise2.default.resolve(value.value).then(function (arg) {
            resume("next", arg);
          }, function (arg) {
            resume("throw", arg);
          });
        } else {
          settle(result.done ? "return" : "normal", result.value);
        }
      } catch (err) {
        settle("throw", err);
      }
    }

    function settle(type, value) {
      switch (type) {
        case "return":
          front.resolve({
            value: value,
            done: true
          });
          break;

        case "throw":
          front.reject(value);
          break;

        default:
          front.resolve({
            value: value,
            done: false
          });
          break;
      }

      front = front.next;

      if (front) {
        resume(front.key, front.arg);
      } else {
        back = null;
      }
    }

    this._invoke = send;

    if (typeof gen.return !== "function") {
      this.return = undefined;
    }
  }

  if (typeof _symbol2.default === "function" && _symbol2.default.asyncIterator) {
    AsyncGenerator.prototype[_symbol2.default.asyncIterator] = function () {
      return this;
    };
  }

  AsyncGenerator.prototype.next = function (arg) {
    return this._invoke("next", arg);
  };

  AsyncGenerator.prototype.throw = function (arg) {
    return this._invoke("throw", arg);
  };

  AsyncGenerator.prototype.return = function (arg) {
    return this._invoke("return", arg);
  };

  return {
    wrap: function wrap(fn) {
      return function () {
        return new AsyncGenerator(fn.apply(this, arguments));
      };
    },
    await: function await(value) {
      return new AwaitValue(value);
    }
  };
}();