buf.toString([encoding[, start[, end]]])

  node.js, question

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encoding[,start
What does this Syntactic sugar mean?
It means that start is optional, but if you want to use the start parameter, do you have to have the encoding parameter?

This is the unique Syntactic sugar in node?

If you look at the nesting relationship between brackets, you can basically infer your understanding.

First of allencodingIn one[]Within, then she is naturally an optional parameter!

Keep looking back, thenencoding, [start]What Do You Mean? again Obviously can feel, is set upencodingIn the case of, there is an optionalstart.

This is a common expression:

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Address:usage-message