is the foreach () in the Node.js synchronous or asynchronous? _node.js

Almost every place in the node where the callback function is used is asynchronous, and the code behind the callback function is likely to be executed first, especially the database operation, after the code in the callback function. Of course, node also provides a synchronized version of a function, such as a file operation, and Fs.readfilesync () is a synchronized version of Fs.readfile ().

So the question is, is ForEach () asynchronous? Logically speaking, without sync, it should be asynchronous.

Copy Code code as follows:

var arr = [' A ', ' B ', ' C '];
var str = ' 123 ';
Arr.foreach (function (item) {
str = + Item;
while (true) {}; With a dead loop, stuck to it!
});
Console.log (str);

Run the above code, and it turns out to be so jammed, without any output.

So, the foreach in node is synchronized!!

The first time with node, did not consider this issue, according to the synchronization of the written, write suddenly thought, after testing a false alarm, thinking that the previous code has been written wrong.

If in some cases, need to asynchronous processing foreach, Google a bit, there is a node-array, you can try ~ ~ Transmission door: Https://github.com/cfsghost/node-array

This work is created by Http://www.cnblogs.com/ImYZF