How to use the warn function from loglevel

Find comprehensive JavaScript loglevel.warn code examples handpicked from public code repositorys.

loglevel.warn is a function provided by the loglevel library that logs a warning message to the console.

56
57
58
59
60
61
62
63
64
65

### AMD (e.g. RequireJS)

```javascript
define(['loglevel'], function(log) {
   log.warn("dangerously convenient");
});
```

### Directly in your web page:
fork icon170
star icon0
watch icon4

+ 3 other calls in file

883
884
885
886
887
888
889
890
891
892
	ltype.pattern.push(curr.value);
	curr = scanner.next();
	break;
case 0:
	log.debug('}');
	if(length > 0 && length !== ltype.pattern.length) log.warn('lengths do not match on LTYPE pattern');
	ltypes[ltypeName] = ltype;
	ltype = {};
	log.debug('LType {');
	curr = scanner.next();
fork icon70
star icon264
watch icon0

How does loglevel.warn work?

loglevel.warn() is a method in the loglevel library that is used to log a warning message to the console with a warning icon. It takes a string or an object as an argument and logs it with a prefix of the word "WARN". The warning message is printed to the console only if the logging level is set to "warn" or lower.

258
259
260
261
262
263
264
265
266
267
### AMD

```javascript
define(['loglevel', 'loglevel-plugin-remote'], function(log, remote) {
  remote.apply(log);
  log.warn('message');
});
```

## Example
fork icon34
star icon91
watch icon2

133
134
135
136
137
138
139
140
141
142
let val;
try {
    val = JSON.parse(String(obj[key]));
} catch(e) {
    let m = `Non-JSON value for ${key} - skipping`;
    log.warn(m);
    stash(m);
    ok = false;
    continue;
}
fork icon27
star icon150
watch icon15

+ 35 other calls in file

Ai Example

1
2
3
4
import log from "loglevel";

log.setLevel("warn");
log.warn("This is a warning message");

In this example, we first import the loglevel library and set the log level to 'warn' using the setLevel method. We then call the warn method on the log object to log a warning message.

105
106
107
108
109
110
111
112
113
114
 * Client video stream error handler.
 *
 * @param {Error} error Camera stream error.
 */
onVideoStreamError(error) {
    log.warn('Can\'t start client video stream', error);
}

/**
 * Stop client webcam video stream.
fork icon18
star icon46
watch icon15

154
155
156
157
158
159
160
161
162
163
  this.phoneTesseract = await this.createTesseractWorker(4, 'eng', this.phoneTimeTesseractOptions);
}

async initializeTimeRemainingTesseract() {
  if (!!this.timeRemainingTesseract) {
    log.warn('Reinitializing time remaining tesseract worker...');
    await this.timeRemainingTesseract.terminate();
  }

  this.timeRemainingTesseract = await this.createTesseractWorker(4, 'eng', this.timeRemainingTesseractOptions);
fork icon20
star icon15
watch icon0

+ 4 other calls in file

538
539
540
541
542
543
544
545
546
547
548
      // Unmount volume root
      execFileSync('umount', [volume_root])


    } catch (err) {
      // Failure
      log.warn(`Couldn't unmount volume root '${volume_root}': ${err.toString()}`)
    }
  }
}

fork icon15
star icon29
watch icon5

+ 244 other calls in file

303
304
305
306
307
308
309
310
311
312
                dxf.tables = parseTables();
                log.debug('<');
        } else if(curr.value === 'EOF') {
                log.debug('EOF');
        } else {
                log.warn('Skipping section \'%s\'', curr.value);
        }
} else {
        curr = scanner.next();
}
fork icon7
star icon8
watch icon3

141
142
143
144
145
146
147
148
149
150
'content-changed': function contentChanged() {
  log.info('[WDS] Content base changed. Reloading...');
  self.location.reload();
},
warnings: function warnings(_warnings) {
  log.warn('[WDS] Warnings while compiling.');
  var strippedWarnings = _warnings.map(function (warning) {
    return stripAnsi(warning);
  });
  sendMsg('Warnings', strippedWarnings);
fork icon0
star icon2
watch icon0

235
236
237
238
239
240
241
242
243
244
245
/**
 * @param {number} distance in meters (> 0)
 */
Hexapod.prototype.goForward = function(distance){
  if(distance > 0) this.pushCmd({name:'goForward', args:[distance]});
  else log.warn("goForward: argument must be greater than zero!")
}


/**
 * @param {number} distance in meters (> 0)
fork icon2
star icon1
watch icon2

+ 5 other calls in file

1
2
3
4
5
6
7
8
9
10
11
12
const logger = require('loglevel')
const { green, red, yellow } = require('kleur')


let logLevel = process.env.LOG_LEVEL || 'info'
if (!['trace', 'debug', 'info', 'warn', 'error'].includes(logLevel)) {
  logger.warn(`Invalid loglevel specified (${logLevel}). Defaulting to 'info'.`)
  logLevel = 'info'
}


const originalFactory = logger.methodFactory
fork icon0
star icon1
watch icon0

+ 3 other calls in file

6
7
8
9
10
11
12
13
14
15
log.setLevel(0)

log.trace('trace')
log.debug('debug')
log.info('info')
log.warn('warn', 'kjhgfbdcxz')
log.error('error')

console.log(log.getLevel())
console.log(log.levels)
fork icon0
star icon1
watch icon0

462
463
464
465
466
467
468
469
470
471
472
473
    .map((tip) => (u.isObject(tip) ? tip.msg : tip))
    .map((tip) => `[require-extension-vue: compiler tip] ${tip}`)
    .filter(templateCompilerTipMessageFilter);


  if (tips.length > 0) {
    log.warn(`[require-extension-vue] compiler tips in file: ${filename}`);
  }


  tips.forEach((tip) => log.warn(tip));
};
fork icon1
star icon0
watch icon3

4
5
6
7
8
9
10
11
12
13
14
15
loglevel.setLevel(parseInt(process.env.LOG_LEVEL || 0));


const trace = loglevel.trace;
const debug = loglevel.debug;
const info  = loglevel.info;
const warn  = loglevel.warn;
const error = loglevel.error;


loglevel.trace = function (a, b) {
  trace(b === undefined ? a : a + ' | ' + b);
fork icon0
star icon1
watch icon2

33
34
35
36
37
38
39
40
41
42

    let questDirectoryParent = path.join(this.questDirectory, '..')
    cd(questDirectoryParent);

    if (test('-d', this.questDirectory)) {
        log.warn(`Remove existing directory: ${this.questDirectory}`)
        rm('-rf', this.questDirectory);
    }
    mkdir(this.questDirectory);
}
fork icon0
star icon0
watch icon0

32
33
34
35
36
37
38
39
40
41
try {
  status = await stove.getStatus()
  log.trace(status)
} catch (e) {
  log.warn('fail to get status')
  log.warn(e)
}
try {
  await mqtt.publish(conf.mqtt.topicOut, JSON.stringify(status))
  log.trace(`message published to ${conf.mqtt.topicOut}`)
fork icon0
star icon0
watch icon0

+ 3 other calls in file