v2_example_text_marshaling_test.go

     1  // Copyright 2018 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build goexperiment.jsonv2
     6  
     7  package json_test
     8  
     9  import (
    10  	"fmt"
    11  	"log"
    12  	"strings"
    13  
    14  	"encoding/json"
    15  )
    16  
    17  type Size int
    18  
    19  const (
    20  	Unrecognized Size = iota
    21  	Small
    22  	Large
    23  )
    24  
    25  func (s *Size) UnmarshalText(text []byte) error {
    26  	switch strings.ToLower(string(text)) {
    27  	default:
    28  		*s = Unrecognized
    29  	case "small":
    30  		*s = Small
    31  	case "large":
    32  		*s = Large
    33  	}
    34  	return nil
    35  }
    36  
    37  func (s Size) MarshalText() ([]byte, error) {
    38  	var name string
    39  	switch s {
    40  	default:
    41  		name = "unrecognized"
    42  	case Small:
    43  		name = "small"
    44  	case Large:
    45  		name = "large"
    46  	}
    47  	return []byte(name), nil
    48  }
    49  
    50  func Example_textMarshalJSON() {
    51  	blob := `["small","regular","large","unrecognized","small","normal","small","large"]`
    52  	var inventory []Size
    53  	if err := json.Unmarshal([]byte(blob), &inventory); err != nil {
    54  		log.Fatal(err)
    55  	}
    56  
    57  	counts := make(map[Size]int)
    58  	for _, size := range inventory {
    59  		counts[size] += 1
    60  	}
    61  
    62  	fmt.Printf("Inventory Counts:\n* Small:        %d\n* Large:        %d\n* Unrecognized: %d\n",
    63  		counts[Small], counts[Large], counts[Unrecognized])
    64  
    65  	// Output:
    66  	// Inventory Counts:
    67  	// * Small:        3
    68  	// * Large:        2
    69  	// * Unrecognized: 3
    70  }
    71
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