Is react js single threaded?
React Native is single-threaded in nature. In its rendering process, rather than have multiple processes occur at the same time (multithreading), other components have to wait when one component is being rendered.
What is single threaded?
Single threaded processes contain the execution of instructions in a single sequence. In other words, one command is processes at a time. The opposite of single threaded processes are multithreaded processes. These processes allow the execution of multiple parts of a program at the same time.
Callbacks that you call yourself are regular function calls, which are always synchronous. Certain native APIs (eg, AJAX, geolocation, Node. js disk or network APIs) are asynchronous and will execute their callbacks later in the event loop.