wishthis/node_modules/rxjs/dist/esm/internal/observable/fromEvent.js
2022-04-07 09:06:43 +02:00

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2.2 KiB
JavaScript

import { innerFrom } from '../observable/innerFrom';
import { Observable } from '../Observable';
import { mergeMap } from '../operators/mergeMap';
import { isArrayLike } from '../util/isArrayLike';
import { isFunction } from '../util/isFunction';
import { mapOneOrManyArgs } from '../util/mapOneOrManyArgs';
const nodeEventEmitterMethods = ['addListener', 'removeListener'];
const eventTargetMethods = ['addEventListener', 'removeEventListener'];
const jqueryMethods = ['on', 'off'];
export function fromEvent(target, eventName, options, resultSelector) {
if (isFunction(options)) {
resultSelector = options;
options = undefined;
}
if (resultSelector) {
return fromEvent(target, eventName, options).pipe(mapOneOrManyArgs(resultSelector));
}
const [add, remove] = isEventTarget(target)
? eventTargetMethods.map((methodName) => (handler) => target[methodName](eventName, handler, options))
:
isNodeStyleEventEmitter(target)
? nodeEventEmitterMethods.map(toCommonHandlerRegistry(target, eventName))
: isJQueryStyleEventEmitter(target)
? jqueryMethods.map(toCommonHandlerRegistry(target, eventName))
: [];
if (!add) {
if (isArrayLike(target)) {
return mergeMap((subTarget) => fromEvent(subTarget, eventName, options))(innerFrom(target));
}
}
if (!add) {
throw new TypeError('Invalid event target');
}
return new Observable((subscriber) => {
const handler = (...args) => subscriber.next(1 < args.length ? args : args[0]);
add(handler);
return () => remove(handler);
});
}
function toCommonHandlerRegistry(target, eventName) {
return (methodName) => (handler) => target[methodName](eventName, handler);
}
function isNodeStyleEventEmitter(target) {
return isFunction(target.addListener) && isFunction(target.removeListener);
}
function isJQueryStyleEventEmitter(target) {
return isFunction(target.on) && isFunction(target.off);
}
function isEventTarget(target) {
return isFunction(target.addEventListener) && isFunction(target.removeEventListener);
}
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