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/**
* A promise that is also tappable, i.e. something you can subscribe
* to to get progress of a promise until it resolves.
*
* @example Usage
* const tp = new TappablePromise((resolve, reject, tap) => {
* for (let i = 0; i < 10; i++) {
* tap(i/10);
* }
* resolve();
* });
*
* tp.tap((progress) => {
* console.log(progress);
* }).then(() => {
* console.log('done');
* });
*
* // Output:
* // 0
* // 0.1
* // 0.2
* // ...
* // 0.9
* // done
*
*
* @param {(resolve: Function, reject: Function, tap: Function) => void} callback
* @returns {Promise & { tap: Function }}}
*/
export default function TappablePromise(callback) {
let progressCallback;
const promise = new Promise((resolve, reject) => {
try {
const tap = (progress) => progressCallback?.(progress);
resolve(callback(tap, resolve, reject));
} catch (e) {
reject(e);
}
});
promise.tap = function tap(_progressCallback) {
progressCallback = _progressCallback;
return this;
};
return promise;
}
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