Example of unmarshalling a JSON string in Go "lazily" to ensure that you at least decode some of the items in the event of an error.

json_marshal_example.go

// Demonstrates how to do "lazy" JSON Unmarshaling if you suspect that the main
// JSON container is formatted correctly but some sub-items may not be formatted
// correctly.

package main

import (
	"encoding/json"
	"log"
)

// CoolData represents cool data
type CoolData struct {
	Name string `json:"name"`
	Cool string `json:"cool"`
}

var correctData = `[
{"name": "Cass", "cool": "true"},
{"name": "Kale", "cool": "true"}
]`

var incorrectData = `[
{"name": "Cass", "cool": "true"},
{"name": "Kale", "cool": true}
]`

func main() {

	// Unmarshal is great when the whole payload is correct
	var correctItems []CoolData

	_ = json.Unmarshal([]byte(correctData), &correctItems)
	log.Println("This is decoded correctly: ", correctItems)

	err := json.Unmarshal([]byte(incorrectData), &correctItems)
	log.Println("This was not Unmarshaled correctly because: ", err)
	log.Println("This is also wasteful because not all of the items in the list were encoded incorrectly, only one of them")

	var maybeCoolData []json.RawMessage
	_ = json.Unmarshal([]byte(correctData), &maybeCoolData)
	log.Println("This is decoded as a list of raw JSON: ", maybeCoolData)

	var allCorrectItems []CoolData
	for _, item := range maybeCoolData {
		var coolItem CoolData
		_ = json.Unmarshal(item, &coolItem)
		allCorrectItems = append(allCorrectItems, coolItem)
	}
	log.Println("We end up with all the correct items: ", allCorrectItems)

	_ = json.Unmarshal([]byte(incorrectData), &maybeCoolData)
	var someCorrectItems []CoolData
	for _, item := range maybeCoolData {
		var maybeCoolItem CoolData
		err = json.Unmarshal(item, &maybeCoolItem)
		if err != nil {
			log.Println("Unable to Unmarshal CoolData because: ", err)
			continue
		}
		someCorrectItems = append(someCorrectItems, maybeCoolItem)
	}

	log.Println("We end up with some of the correct items: ", someCorrectItems)
}