Are there significant differences between the Chrome browser event loop versus the node event loop?

Question

Philip Roberts does a brilliant job explaining the browser event loop here providing a clear explanation between the call stack, event loop, task queue, and then \"outside\" thr

Answer 1

Both are quite different. Browser's event loop doesn't depends on I/O Operations. But Node js event loop depends on I/O operations. Here the Node js event loop main goal is to separate out the main process and try to execute I/O operations and other timer API's asynchronously.

And another difference is we don't have a function setImmediate() in Browser. Difference between setTimeout() and setImmediate() is In setTimeout() call back function will execute after the given minimum threshold value in milliseconds. But in setImmediate() once any I/O Operation is done, if particular code is given inside setImmediate(), it will be executed first.

Because normally

setTimeout(() => {
    //some process
}, 0);

and

setImmediate(() => {
    //some process
});

are same and we can't predict which will execute first. But in Node js perspective under nodejs event loop mechanism if both are present under the callback of any I/O Operation, setImmediate() will get executed first. so,

let fs = require('fs');
fs.readFile('/file/path', () => {
   setTimeout(() => {
      console.log('1');
   }, 0);
   setImmediate(() => {
      console.log('2');
   });
});

The output for above code will be,

2
1