When does `json.Unmarshal()` return an error in Go?

When Does json.Unmarshal() Return Error in Go?

Json.Unmarshal() is a function in Go that decodes JSON data into a structured variable. By default, it does not report an error when there is a mismatch between the source data and the target struct.

However, errors can arise in several scenarios:

• Syntax Errors: If the JSON data contains syntax errors, such as missing start or end characters, json.Unmarshal() will return an error.

• Type Mismatch: When the JSON value cannot be assigned to the corresponding field in the struct, json.Unmarshal() returns an error. For instance:

  • Trying to assign a boolean value to a string field
  • Trying to assign an array to a struct field

• Target Type Not Representable: If the value of a JSON field cannot be represented by the target struct, an error is returned. This can happen in cases like:

  • Trying to decode a JSON array into a string variable

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