JSON unmarshaller for custom types

main.go

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"strings"
	"time"
)

type (
	Bool     bool
	DateTime time.Time

	Tweet struct {
		Id        uint64   `json:"id"`
		Text      string   `json:"text"`
		IsRetweet Bool     `json:"isRetweet"`
		IsDeleted Bool     `json:"isDeleted"`
		Device    string   `json:"device"`
		Favorites uint32   `json:"favorites"`
		Retweets  uint32   `json:"retweets"`
		Date      DateTime `json:"date"`
		IsFlagged Bool     `json:"isFlagged"`
	}
)

var tweets []Tweet

func (t Tweet) String() string {
	return fmt.Sprintf("%s: %s", time.Time(t.Date).Format("2006-01-02 15:04:05"), t.Text)
}

func (b *Bool) UnmarshalJSON(bytes []byte) error {
	*b = bytes[1] == 't'
	return nil
}

func (dt *DateTime) UnmarshalJSON(bytes []byte) error {
	var s string
	if err := json.Unmarshal(bytes, &s); check(err) {
		if d, err := time.Parse("2006-01-02 15:04:05", s); check(err) {
			*dt = DateTime(d)
		}
	}
	return nil
}

func check(err error) bool {
	if err != nil {
		panic(err)
	}
	return true
}

func main() {
	// tweets_01-08-2021.json downloaed from https://www.thetrumparchive.com/
	if jsonFile, err := ioutil.ReadFile("tweets_01-08-2021.json"); check(err) {
		json.Unmarshal(jsonFile, &tweets)

		fmt.Println(len(tweets))
		for _, tweet := range tweets {
			if strings.Contains(tweet.Text, "I.Q.") {
				fmt.Println(tweet)
			}
		}
	}
}