5 examples of 'async const function' in JavaScript

34
return function asyncFunction() {
35
  const args = Array.from(arguments);
36
  return new Promise(function (resolve, reject) {
37
    let gen;
38
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    function step(next) {
40
      const value = next.value;
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      if (next.done) {
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        return resolve(value);
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      }
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      if (value instanceof Promise) {
45
        return value.then(
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          result => step(gen.next(result)),
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          error => {
48
            try {
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              step(gen.throw(error));
50
            } catch (err) {
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              throw err;
52
            }
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          }
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        ).catch((err) => {
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          warn("Unhandled error in async function.", err);
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          reject(err);
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        });
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      }
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      step(gen.next(value));
60
    }
61
62
    if (typeof func !== "function") {
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      reject(new TypeError("Expected a Function."));
64
    }
65
    // not a generator, wrap it.
66
    if (func.constructor.name !== "GeneratorFunction") {
67
      gen = (function*() {
68
        return func.call(self, ...args);
69
      }());
70
    } else {
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      gen = func.call(self, ...args);
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    }
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    try {
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      step(gen.next());
75
    } catch (err) {
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      warn("The generator threw immediately.", err);
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      reject(err);
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    }
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  });
80
};

50
function _async (_function) {
51
	return function () {
52
		var
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			m = this,
54
			_arguments = arguments
55
		;
56
		setTimeout (function () {_function.apply (m,_arguments)},0);
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	};
58
}

149
exports.async = function asyncFunction(iter) {
150
  return new Promise((resolve, reject) => {
151
    resume('next', undefined);
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    function resume(type, value) {
153
      try {
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        let result = iter[type](value);
155
        if (result.done) {
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          resolve(result.value);
157
        } else {
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          Promise.resolve(result.value).then(
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            x => resume('next', x),
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            x => resume('throw', x));
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        }
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      } catch (x) {
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        reject(x);
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      }
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    }
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  });
167
};

325
function constFunc(func) {
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  Object.freeze(func.prototype);
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  return Object.freeze(func);
328
}

143
value: function async(callback) {
144
    for (var _len4 = arguments.length, args = Array(_len4 > 1 ? _len4 - 1 : 0), _key4 = 1; _key4 < _len4; _key4++) {
145
        args[_key4 - 1] = arguments[_key4];
146
    }
147
148
    var deferred = new Deferred();
149
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    setTimeout(function () {
151
        try {
152
            var result = callback.apply(deferred, args);
153
            deferred.resolve(result);
154
        } catch (err) {
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            deferred.reject(err);
156
        }
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    }, 0);
158
159
    return deferred;
160
}