Code snippet in `Consume decoded JSON strings` in `How to use a JSON document, Utf8JsonReader, and Utf8JsonWriter in System.Text.Json` does not compile

[konrad-jamrozik]

I copy-pasted the code snippet from Consume decoded JSON strings section into my Visual Studio:

int valueLength = reader.HasReadOnlySequence 
    ? checked((int)ValueSequence.Length) 
    : ValueSpan.Length;

char[] buffer = ArrayPool<char>.Shared.Rent(valueLength);
int charsRead = reader.CopyString(buffer);
ReadOnlySpan<char> source = buffer.Slice(0, charsRead);

// Handle the unescaped JSON string.
ParseUnescapedString(source);
ArrayPool<char>.Shared.Return(buffer, clearArray: true);

and here is what I got:

all the symbols marked in red are not recognized. I searched a bit and looks like this is not a problem with my setup.

For example, Utf8JsonReader doesn't appear to have a HasReadOnlySequence member.

It is also a bit confusing that the section says:

The following code snippet shows an example of consuming a UTF-16 string using CopyString.

but refers to UTF-8. So is it UTF-8 or UTF-16 ?

I think the doc should provide near-obviously-compilable code snippets. At the very least it should explain what needs to be done to make the snippet compile, like what dependencies to import to get the right Slice method, how to implement ParseUnescapedString and so on.

Related:

• How to write custom converters for JSON serialization (marshalling) in .NET should explain how to handle complex types #35020
• The documentation on using Utf8JsonReader should explain how to obtain different kinds of objects from it, like e.g. JsonNode. #35021

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Document Details

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• ID: 73a13d38-4904-c068-c9eb-e43176ce5338
• Version Independent ID: c5dfa4d2-c77a-e752-dae7-0bfae5756b76
• Content: How to use a JSON document, Utf8JsonReader, and Utf8JsonWriter in System.Text.Json
• Content Source: docs/standard/serialization/system-text-json/use-dom-utf8jsonreader-utf8jsonwriter.md
• Product: dotnet-fundamentals
• GitHub Login: @gewarren
• Microsoft Alias: gewarren

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Associated WorkItem - 91665