Anything that does significant work that would otherwise result in an unresponsive UI. For example code on the following page is compiled as you type, without a

Anything that does significant work that would otherwise result in an unresponsive UI. For example code on the following page is compiled as you type, without a webworker this would give a very horrible user experience because compilation can take a long time for very large input - https://codemix.github.io/flow-runtime/#/try https://codemix.github.io/flow-runtime/#/try