A simple JSON stringify function which requires Array.prototype.map method.
The following users provided lots of ideas and improvements of the code.
@Kambfhase, @hartrock, @atk, @haochi, @jed
Actually, I just provided a deficient version at first. The other versions were created by these users(especially @atk). You may see the discussion below.
@jed Thanks, the tip is great! I think it should be written in the Byte-Saving Techniques.
@atk Thanks as well. But I think the code is missing something...