@aws-amplify/core
Version:
Core category of aws-amplify
121 lines (119 loc) • 3.82 kB
JavaScript
;
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
Object.defineProperty(exports, "__esModule", { value: true });
exports.HubInternal = exports.Hub = exports.HubClass = exports.AMPLIFY_SYMBOL = void 0;
const Logger_1 = require("../Logger");
const constants_1 = require("../constants");
const errors_1 = require("../errors");
exports.AMPLIFY_SYMBOL = (typeof Symbol !== 'undefined'
? Symbol('amplify_default')
: '@@amplify_default');
const logger = new Logger_1.ConsoleLogger('Hub');
class HubClass {
constructor(name) {
this.listeners = new Map();
this.protectedChannels = [
'core',
'auth',
'api',
'analytics',
'interactions',
'pubsub',
'storage',
'ui',
'xr',
];
this.name = name;
}
/**
* Used internally to remove a Hub listener.
*
* @remarks
* This private method is for internal use only. Instead of calling Hub.remove, call the result of Hub.listen.
*/
_remove(channel, listener) {
const holder = this.listeners.get(channel);
if (!holder) {
logger.warn(`No listeners for ${channel}`);
return;
}
this.listeners.set(channel, [
...holder.filter(({ callback }) => callback !== listener),
]);
}
dispatch(channel, payload, source, ampSymbol) {
if (typeof channel === 'string' &&
this.protectedChannels.indexOf(channel) > -1) {
const hasAccess = ampSymbol === exports.AMPLIFY_SYMBOL;
if (!hasAccess) {
logger.warn(`WARNING: ${channel} is protected and dispatching on it can have unintended consequences`);
}
}
const capsule = {
channel,
payload: { ...payload },
source,
patternInfo: [],
};
try {
this._toListeners(capsule);
}
catch (e) {
logger.error(e);
}
}
listen(channel, callback, listenerName = 'noname') {
let cb;
if (typeof callback !== 'function') {
throw new errors_1.AmplifyError({
name: constants_1.NO_HUBCALLBACK_PROVIDED_EXCEPTION,
message: 'No callback supplied to Hub',
});
}
else {
// Needs to be casted as a more generic type
cb = callback;
}
let holder = this.listeners.get(channel);
if (!holder) {
holder = [];
this.listeners.set(channel, holder);
}
holder.push({
name: listenerName,
callback: cb,
});
return () => {
this._remove(channel, cb);
};
}
_toListeners(capsule) {
const { channel, payload } = capsule;
const holder = this.listeners.get(channel);
if (holder) {
holder.forEach(listener => {
logger.debug(`Dispatching to ${channel} with `, payload);
try {
listener.callback(capsule);
}
catch (e) {
logger.error(e);
}
});
}
}
}
exports.HubClass = HubClass;
/* We export a __default__ instance of HubClass to use it as a
pseudo Singleton for the main messaging bus, however you can still create
your own instance of HubClass() for a separate "private bus" of events. */
exports.Hub = new HubClass('__default__');
/**
* @internal
*
* Internal hub used for core Amplify functionality. Not intended for use outside of Amplify.
*
*/
exports.HubInternal = new HubClass('internal-hub');
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