Function keep

Converts a Promise into an Observable which fires once. Any exceptions thrown while awaiting the promise will be re-thrown. If an exception is thrown the observer will definitely not be called.

Remarks

A Promise may be thought of as a linear Observable; an Observable may be thought of as a non-linear Promise.

Example

const promise = keep(new Promise((resolve) => {
  setTimeout(() => {
    resolve("hello from 2 seconds ago");
  }, 2000);
}));
const activity = promise.subscribe(
  (msg: string) => void console.log(msg)
);
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Example

# prints
hello from 2 seconds ago
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