MobxPromise

Provides observable status and results from computed promises to make it easy to render MobX observer components from changing, asynchronous data with mobx-react.

A MobxPromise (MP) is integrated into an application by referencing its computed properties (status, result, ...) in the render method of an observer component. Thanks to mobx-react, the component's render function will be re-invoked whenever the properties of the referenced MP change. The status of the MP and its resulting data will thus be reflected as a product of reference, with no other wiring necessary.

How does this happen? A reference to any property of the MP invokes that property's @computed getter. The getter first checks the status of any MP in the await collection (and this causes the same process to occur inside these children). If any awaited promises are not complete (i.e. status is "error" or "pending") then that is assumed to be the status of the awaiting MP. If all awaited promises are complete, then the MP accesses its @computed promise using the provided invoke method.

When the promise resolves, the MP's status is set to "complete" unless the promise has become stale or members of the await collection no longer have a status of "complete". The computed promise becomes stale when observable dependencies of the invoke function have changed. Promises which become stale before being resolved will never set the status or result of the MP and will thus have no influence on the application. Thanks to MobX, the invoke method will only be called again when its referenced observables have changed.

Acknowledgements

Thanks to @alisman for writing a big chunk of this readme.

Thanks to the @cBioPortal team for feedback which helped shape this little utility class.

This project was set up using TypeScript library starter.