debug-level/examples/jsonOutput.cjs at main · commenthol/debug-level · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
const { Log } = require('..')
Log.options({ level: 'DEBUG', json: true, serverinfo: true, spaces: 2 })

const log = new Log('package')

// ----
// use formatters (NOT RECOMMENDED for objects, errors)
log.debug(
  'a %s, a number %d, an %o and %j',
  'string',
  1.2,
  { object: 1 },
  { NOT: 'RECOMMENDED' }
)
/* > {
  "level": "DEBUG",
  "name": "package",
  "msg": "a string, a number 1.2, an {\n  \"object\": 1\n} and {\n  \"NOT\": "RECOMMENDED"\n}",
  "hostname": "server",
  "pid": 3804,
  "diff": 0
} */

// ----
// objects get merged/ assigned - string overwrites msg
log.debug({ object: 1 }, { json: true }, [1, 2, 3], '%s #%d', 'message', 1)
/* > {
  "level": "DEBUG",
  "name": "package",
  "msg": "message #1",
  "object": 1,
  "json": true,
  "arr": [1, 2, 3],
  "hostname": "server",
  "pid": 3804,
  "diff": 0
} */

// ----
const err = new Error('baam')
err.status = 500

// error - string overwrites msg
log.error(err, { object: 1 }, 'A very bad Error')
/* > {
  "level": "ERROR",
  "name": "package",
  "msg": "A very bad Error",
  "err": {
    "name": "Error",
    "stack": "Error: baam\n    ...\n    at bootstrap_node.js:608:3",
    "status": 500
  },
  "object": 1,
  "hostname": "server",
  "pid": 3804,
  "diff": 20
} */

// ----
// only last arr remains in log
log.debug([1, 2, 3], [4, 5, 6])
/* > {
  "level": "DEBUG",
  "name": "package",
  "arr": [4, 5, 6],
  "hostname": "server",
  "pid": 3804,
  "diff": 3
} */

// additional arguments get added as `args`
log.info('formatter %s', 'message1', 'message2', 'message3')
/* > {
  "level": "INFO",
  "name": "package",
  "msg": "formatter message1",
  "args": ["message2", "message3"],
  "hostname": "server",
  "pid": 3804,
  "diff": 0
} */

// ----
// using toJSON custom serializers
function reqToJSON() {
  const { ip, method, url, headers } = this
  const userAgent = headers ? headers['user-agent'] : undefined
  return { ip, method, url, userAgent }
}

const req = {
  // a client request
  method: 'GET',
  url: '/path',
  ip: '10.10.10.10',
  headers: { 'user-agent': 'debug-level/1.0' },
  socket: {} // ....
}
req.toJSON = reqToJSON

function resToJSON() {
  const { statusCode } = this
  return { statusCode }
}

const res = {
  // a server response
  statusCode: 403,
  socket: {} // ....
}
res.toJSON = resToJSON

log.warn({ req, res })
/* > {
  "level": "WARN",
  "name": "package",
  "req": {
    "ip": "10.10.10.10",
    "method": "GET",
    "url": "/path",
    "userAgent": "debug-level/1.0"
  },
  "res": {
    "statusCode": 403
  },
  "hostname": "server",
  "pid": 3804,
  "diff": 1
} */