👀 Views: 31 💬 Answers: 1 📅 Created: 2025-06-11

json go encoding/json Go

I'm working through a tutorial and I'm building a feature where I'm not sure how to approach I am having trouble deserializing a deeply nested JSON structure that contains mixed data types in Go using the `encoding/json` package... The JSON response from my API looks like this: ```json { "user": { "name": "John Doe", "age": 30, "contacts": [ { "type": "email", "value": "john@example.com" }, { "type": "phone", "value": "+1234567890" } ], "isActive": true, "metadata": { "lastLogin": "2023-09-21T12:34:56Z", "preferences": { "language": "en", "timezone": "UTC" } } } } ``` I defined my struct like this: ```go type Contact struct { Type string `json:"type"` Value string `json:"value"` } type Metadata struct { LastLogin string `json:"lastLogin"` Preferences struct { Language string `json:"language"` Timezone string `json:"timezone"` } `json:"preferences"` } type User struct { Name string `json:"name"` Age int `json:"age"` Contacts []Contact `json:"contacts"` IsActive bool `json:"isActive"` Metadata Metadata `json:"metadata"` } ``` When I attempt to unmarshal the JSON into a `User` struct like this: ```go var user User err := json.Unmarshal([]byte(jsonString), &user) if err != nil { log.Fatalf("behavior unmarshaling JSON: %v", err) } ``` I receive the behavior: `json: want to unmarshal string into Go struct field Metadata.preferences of type struct { Language string; Timezone string }`. It appears that the nested JSON for `preferences` is not being interpreted correctly. What am I missing here? I've confirmed that the JSON structure matches the struct definitions, but I suspect that the scenario arises from the nested struct definition for `Preferences`. I've also tried adding explicit types for the `Preferences` field but it hasn't resolved the scenario. Any insights on how to properly handle this kind of nested JSON structure without running into type issues would be highly appreciated. Thanks! What am I doing wrong? For reference, this is a production mobile app. How would you solve this?