debian-mirror-gitlab/core-js/modules/esnext.observable.js
2019-10-31 01:37:42 +05:30

207 lines
6.9 KiB
JavaScript

'use strict';
// https://github.com/tc39/proposal-observable
var $ = require('../internals/export');
var DESCRIPTORS = require('../internals/descriptors');
var setSpecies = require('../internals/set-species');
var aFunction = require('../internals/a-function');
var anObject = require('../internals/an-object');
var isObject = require('../internals/is-object');
var anInstance = require('../internals/an-instance');
var defineProperty = require('../internals/object-define-property').f;
var createNonEnumerableProperty = require('../internals/create-non-enumerable-property');
var redefineAll = require('../internals/redefine-all');
var getIterator = require('../internals/get-iterator');
var iterate = require('../internals/iterate');
var hostReportErrors = require('../internals/host-report-errors');
var wellKnownSymbol = require('../internals/well-known-symbol');
var InternalStateModule = require('../internals/internal-state');
var OBSERVABLE = wellKnownSymbol('observable');
var getInternalState = InternalStateModule.get;
var setInternalState = InternalStateModule.set;
var getMethod = function (fn) {
return fn == null ? undefined : aFunction(fn);
};
var cleanupSubscription = function (subscriptionState) {
var cleanup = subscriptionState.cleanup;
if (cleanup) {
subscriptionState.cleanup = undefined;
try {
cleanup();
} catch (error) {
hostReportErrors(error);
}
}
};
var subscriptionClosed = function (subscriptionState) {
return subscriptionState.observer === undefined;
};
var close = function (subscription, subscriptionState) {
if (!DESCRIPTORS) {
subscription.closed = true;
var subscriptionObserver = subscriptionState.subscriptionObserver;
if (subscriptionObserver) subscriptionObserver.closed = true;
} subscriptionState.observer = undefined;
};
var Subscription = function (observer, subscriber) {
var subscriptionState = setInternalState(this, {
cleanup: undefined,
observer: anObject(observer),
subscriptionObserver: undefined
});
var start;
if (!DESCRIPTORS) this.closed = false;
try {
if (start = getMethod(observer.start)) start.call(observer, this);
} catch (error) {
hostReportErrors(error);
}
if (subscriptionClosed(subscriptionState)) return;
var subscriptionObserver = subscriptionState.subscriptionObserver = new SubscriptionObserver(this);
try {
var cleanup = subscriber(subscriptionObserver);
var subscription = cleanup;
if (cleanup != null) subscriptionState.cleanup = typeof cleanup.unsubscribe === 'function'
? function () { subscription.unsubscribe(); }
: aFunction(cleanup);
} catch (error) {
subscriptionObserver.error(error);
return;
} if (subscriptionClosed(subscriptionState)) cleanupSubscription(subscriptionState);
};
Subscription.prototype = redefineAll({}, {
unsubscribe: function unsubscribe() {
var subscriptionState = getInternalState(this);
if (!subscriptionClosed(subscriptionState)) {
close(this, subscriptionState);
cleanupSubscription(subscriptionState);
}
}
});
if (DESCRIPTORS) defineProperty(Subscription.prototype, 'closed', {
configurable: true,
get: function () {
return subscriptionClosed(getInternalState(this));
}
});
var SubscriptionObserver = function (subscription) {
setInternalState(this, { subscription: subscription });
if (!DESCRIPTORS) this.closed = false;
};
SubscriptionObserver.prototype = redefineAll({}, {
next: function next(value) {
var subscriptionState = getInternalState(getInternalState(this).subscription);
if (!subscriptionClosed(subscriptionState)) {
var observer = subscriptionState.observer;
try {
var nextMethod = getMethod(observer.next);
if (nextMethod) nextMethod.call(observer, value);
} catch (error) {
hostReportErrors(error);
}
}
},
error: function error(value) {
var subscription = getInternalState(this).subscription;
var subscriptionState = getInternalState(subscription);
if (!subscriptionClosed(subscriptionState)) {
var observer = subscriptionState.observer;
close(subscription, subscriptionState);
try {
var errorMethod = getMethod(observer.error);
if (errorMethod) errorMethod.call(observer, value);
else hostReportErrors(value);
} catch (err) {
hostReportErrors(err);
} cleanupSubscription(subscriptionState);
}
},
complete: function complete() {
var subscription = getInternalState(this).subscription;
var subscriptionState = getInternalState(subscription);
if (!subscriptionClosed(subscriptionState)) {
var observer = subscriptionState.observer;
close(subscription, subscriptionState);
try {
var completeMethod = getMethod(observer.complete);
if (completeMethod) completeMethod.call(observer);
} catch (error) {
hostReportErrors(error);
} cleanupSubscription(subscriptionState);
}
}
});
if (DESCRIPTORS) defineProperty(SubscriptionObserver.prototype, 'closed', {
configurable: true,
get: function () {
return subscriptionClosed(getInternalState(getInternalState(this).subscription));
}
});
var $Observable = function Observable(subscriber) {
anInstance(this, $Observable, 'Observable');
setInternalState(this, { subscriber: aFunction(subscriber) });
};
redefineAll($Observable.prototype, {
subscribe: function subscribe(observer) {
var length = arguments.length;
return new Subscription(typeof observer === 'function' ? {
next: observer,
error: length > 1 ? arguments[1] : undefined,
complete: length > 2 ? arguments[2] : undefined
} : isObject(observer) ? observer : {}, getInternalState(this).subscriber);
}
});
redefineAll($Observable, {
from: function from(x) {
var C = typeof this === 'function' ? this : $Observable;
var observableMethod = getMethod(anObject(x)[OBSERVABLE]);
if (observableMethod) {
var observable = anObject(observableMethod.call(x));
return observable.constructor === C ? observable : new C(function (observer) {
return observable.subscribe(observer);
});
}
var iterator = getIterator(x);
return new C(function (observer) {
iterate(iterator, function (it) {
observer.next(it);
if (observer.closed) return iterate.stop();
}, undefined, false, true);
observer.complete();
});
},
of: function of() {
var C = typeof this === 'function' ? this : $Observable;
var length = arguments.length;
var items = new Array(length);
var index = 0;
while (index < length) items[index] = arguments[index++];
return new C(function (observer) {
for (var i = 0; i < length; i++) {
observer.next(items[i]);
if (observer.closed) return;
} observer.complete();
});
}
});
createNonEnumerableProperty($Observable.prototype, OBSERVABLE, function () { return this; });
$({ global: true }, {
Observable: $Observable
});
setSpecies('Observable');