teste.go

package main

import (
	"bytes"
	"fmt"
	"strings"

	"github.com/diegoholiveira/jsonlogic"
)

func main() {
	jsonOriginal := `{
		"paymentMethods": [
			{
				"name": "payment.method.creditcard.visa",
				"installments": "1",
				"amount": 19,
				"discount": 0,
				"addition": 0,
				"boletoRule": null,
				"interestValue": 0,
				"boletoUrl": "teste",
				"creditCardToken": null
			}
		]
	}`

	data := strings.NewReader(jsonOriginal)

	var result bytes.Buffer

	logic := strings.NewReader(`{"if":[
		{"some": [
			{"var": "paymentMethods"},
			{"==": [
				{"var": ".name"},
				"payment.method.creditcard.mastercard"
			]}
		]},
		"encontrou",
		"não encontrou"
	]}`)

	err := jsonlogic.Apply(logic, data, &result)
	if err != nil {
		panic(err)
	}

	fmt.Println(result.String())
}