node.js - buf.toString([encoding[, start[, end]]])

Question

encoding[,start
这种语法糖什么意思啊，
是代表start 是可选的，但是如果要使用start参数，必须要有encoding 参数吗？

这个是node 里面特有的语法糖？

Answer 1

You can basically infer your understanding by looking at the nesting relationship between brackets.

First of all, encoding is within one [], then she is naturally an optional parameter!

Looking further, what does encoding, [start] mean? Obviously, it can be felt that when encoding is set, there is an optional start after it.

This is a common expression:

Address: usage-message

Answer 2

[] table is optional, meaning there are 4 parameter modes:

Empty
encoding
encoding, start
encoding, start, end