Accessing context from useEffect

If your busyIndicator is not changed during the life of the component, you could simply add it as a dependency to useEffect:

const busyIndicator = useContext(GlobalBusyIndicatorContext);

useEffect(() => {
    busyIndicator.show('Please wait...');
}, [busyIndicator]);

If busyIndicator could be changed and you don't want to see an error, then you could use useRef hook:

const busyIndicator = useRef(useContext(GlobalBusyIndicatorContext));

useEffect(() => {
    busyIndicator.current.show('Please wait...');
}, []);

The useRef() Hook isn’t just for DOM refs. The “ref” object is a generic container whose current property is mutable and can hold any value, similar to an instance property on a class. read more

No need to Wrap your useContext in useRef Hook. you can update your context data just call in useEffect Brackets like this.

const comingData = useContext(taskData);

useEffect(() => {
console.log("Hi useEffect");
}},[comingData]); //context data is updating here before render the component