Rxjs simple implementation
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function map(transformFn) { | |
const inputObservable = this | |
const outputObservable = createObservable(function subscribe(outputObserver) { | |
inputObservable.subscribe({ | |
next: function nextCallback(data) { | |
outputObserver.next(transformFn(data)) | |
}, | |
error: (err) => outputObserver.error(err), | |
complete: () => outputObserver.complete() | |
}) | |
}) | |
return outputObservable | |
} | |
function filter(conditionFn) { | |
const inputObservable = this | |
const outputObservable = createObservable(function subscribe(outputObserver) { | |
inputObservable.subscribe({ | |
next: function nextCallback(data) { | |
if (conditionFn(data)) { | |
outputObserver.next(data) | |
} | |
}, | |
error: (err) => outputObserver.error(err), | |
complete: () => outputObserver.complete() | |
}) | |
}) | |
return outputObservable | |
} | |
function createObservable (subscribe) { | |
return { | |
subscribe: subscribe, | |
map: map, | |
filter: filter | |
} | |
} | |
const arrayObservable = createObservable(function subscribe(ob){ | |
[1,2,3,4].forEach(ob.next) | |
ob.complete() | |
}) | |
const clickObservable = createObservable(function subscribe(ob){ | |
document.addEventListener('click', ob.next) | |
}) | |
const mousemoveObservable = createObservable(function subscribe(ob){ | |
document.addEventListener('mousemove', ob.next) | |
}) | |
const batteryObservable = createObservable(function subscribe(ob) { | |
navigator.getBattery().then((battery) => battery.addEventListener('chargingchange', ob.next)); | |
}) | |
const observer = { | |
next: function nextCallback(data) { | |
console.log(data) | |
}, | |
error: function errorCallback(err) { | |
console.error(err) | |
}, | |
complete: function completeCallback() { | |
console.log('done') | |
} | |
} | |
batteryObservable | |
.map(event => event.currentTarget.level) | |
//.filter(x => x > 200) | |
.subscribe(observer) |
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