MobX Quick Start Guide

Querying the reactive system

When dealing with the various abstractions in MobX (observables, actions, reactions), it is sometimes useful to know if a certain object, function, or value is of a certain kind. MobX has a set of isXXX APIs that help you to determine the type of the value:

• isObservableObject(thing), isObservableArray(thing), isObservableMap(thing): Tells you whether the passed in value is an observable object, array, or map
• isObservable(thing) and isObservableProp(thing, property?): Similar to the preceding point but more generalized check for an observable value
• isBoxedObservable(thing): Whether the value is a boxed observable
• isAction(func): Returns true if the function is wrapped by an action
• isComputed(thing) and isComputedProp(thing, ...