golike-defer/dist/index.js

go's defer statement in JavaScript

"use strict";

exports.__esModule = true;
exports.default = exports.defer = void 0;
var push = Array.prototype.push;

var toDecorator = function toDecorator(wrap) {
  return function (target, key, descriptor) {
    if (key === undefined) {
      return wrap(target);
    }

    descriptor.value = wrap(descriptor.value);
    return descriptor;
  };
};

var setFnNameAndLength = function () {
  var _defineProperties = Object.defineProperties;

  try {
    var f = _defineProperties(function () {}, {
      length: {
        value: 2
      },
      name: {
        value: "foo"
      }
    });

    if (f.length === 2 && f.name === "foo") {
      return function (fn, name, length) {
        return _defineProperties(fn, {
          length: {
            configurable: true,
            value: length > 0 ? length : 0
          },
          name: {
            configurable: true,
            value: name
          }
        });
      };
    }
  } catch (_) {}

  return function (f) {
    return f;
  };
}();

var defaultOnError = function defaultOnError(error) {
  console.error(error);
};

var SUCCESS = 1 << 0;
var FAILURE = 1 << 1;

function Deferred(fn, thisArg, args, when) {
  this.args = args;
  this.fn = fn;
  this.thisArg = thisArg;
  this.when = when;
}

Deferred.prototype.run = function (when) {
  if ((when & this.when) !== 0) {
    return this.fn.apply(this.thisArg, this.args);
  }
};

function defer(fn, onError) {
  if (onError === void 0) {
    onError = defaultOnError;
  }

  var wrapper = function wrapper() {
    var deferreds = [];

    var makeAddDeferred = function makeAddDeferred(when) {
      return function $defer(deferred) {
        var args;

        if (typeof deferred !== "function") {
          deferred = this[deferred];
        }

        var nArgs = arguments.length - 1;

        if (nArgs !== 0) {
          args = new Array(nArgs);

          for (var _i = 0; _i < nArgs; ++_i) {
            args[_i] = arguments[_i + 1];
          }
        }

        deferreds.push(new Deferred(deferred, this, args, when));
      };
    };

    var $defer = makeAddDeferred(FAILURE | SUCCESS);
    $defer.onFailure = makeAddDeferred(FAILURE);
    $defer.onSuccess = makeAddDeferred(SUCCESS);
    var args = [$defer];
    push.apply(args, arguments);
    var hasThrown, result;

    try {
      result = fn.apply(this, args);
      var then;

      if (result != null && typeof (then = result.then) === "function") {
        var executeAndForward = function executeAndForward(when) {
          var i = deferreds.length;

          var loop = function loop() {
            if (i === 0) {
              return result;
            }

            try {
              var _result = deferreds[--i].run(when);

              var _then;

              return _result != null && typeof (_then = _result.then) === "function" ? _then.call(_result, loop, reportAndLoop) : loop();
            } catch (error) {
              return reportAndLoop(error);
            }
          };

          var reportAndLoop = function reportAndLoop(error) {
            onError(error);
            return loop();
          };

          return loop();
        };

        return then.call(result, function () {
          return executeAndForward(SUCCESS);
        }, function () {
          return executeAndForward(FAILURE);
        });
      }

      hasThrown = false;
    } catch (error) {
      result = error;
      hasThrown = true;
    }

    var when = hasThrown ? FAILURE : SUCCESS;
    var i = deferreds.length;

    while (i > 0) {
      try {
        deferreds[--i].run(when);
      } catch (error) {
        onError(error);
      }
    }

    if (hasThrown) {
      throw result;
    }

    return result;
  };

  var length = fn.length;
  return setFnNameAndLength(wrapper, `defer(${fn.name})`, length > 0 ? length - 1 : length);
}

var decorator = toDecorator(defer);
exports.default = exports.defer = decorator;

decorator.onError = function (cb) {
  return toDecorator(function (fn) {
    return defer(fn, cb);
  });
};
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