If that JSON string is 100MB long, too bad, it has to be read completely and allocated again for you to work on because you can only accept a byte array to parse.
I was not sure whether this was the case, as `json.NewEncoder(io.Writer)` and `json.NewDecoder(io.Reader)` exist in v1, so I had checked, and guess what, you're right! Decode() actually reads the value to internal buffer before doing any marshalling in the first place. I had always assumed that it kept internal stack of some kind, for matching-parenthesis and type safety stuff within streaming context, but no, it doesn't do any of that stuff! Come think of it: it does make sense, as partial-unmarshal would be potentially devastating for incrementally-updated data structures as it would leave them to inconsistent state.
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I was not sure whether this was the case, as `json.NewEncoder(io.Writer)` and `json.NewDecoder(io.Reader)` exist in v1, so I had checked, and guess what, you're right! Decode() actually reads the value to internal buffer before doing any marshalling in the first place. I had always assumed that it kept internal stack of some kind, for matching-parenthesis and type safety stuff within streaming context, but no, it doesn't do any of that stuff! Come think of it: it does make sense, as partial-unmarshal would be potentially devastating for incrementally-updated data structures as it would leave them to inconsistent state.