217 lines
5.8 KiB
Markdown
217 lines
5.8 KiB
Markdown
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# npmlog
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The logger util that npm uses.
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This logger is very basic. It does the logging for npm. It supports
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custom levels and colored output.
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By default, logs are written to stderr. If you want to send log messages
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to outputs other than streams, then you can change the `log.stream`
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member, or you can just listen to the events that it emits, and do
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whatever you want with them.
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# Installation
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```console
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npm install npmlog --save
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```
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# Basic Usage
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```javascript
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var log = require('npmlog')
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// additional stuff ---------------------------+
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// message ----------+ |
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// prefix ----+ | |
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// level -+ | | |
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// v v v v
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log.info('fyi', 'I have a kitty cat: %j', myKittyCat)
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```
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## log.level
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* {String}
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The level to display logs at. Any logs at or above this level will be
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displayed. The special level `silent` will prevent anything from being
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displayed ever.
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## log.record
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* {Array}
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An array of all the log messages that have been entered.
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## log.maxRecordSize
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* {Number}
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The maximum number of records to keep. If log.record gets bigger than
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10% over this value, then it is sliced down to 90% of this value.
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The reason for the 10% window is so that it doesn't have to resize a
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large array on every log entry.
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## log.prefixStyle
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* {Object}
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A style object that specifies how prefixes are styled. (See below)
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## log.headingStyle
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* {Object}
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A style object that specifies how the heading is styled. (See below)
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## log.heading
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* {String} Default: ""
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If set, a heading that is printed at the start of every line.
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## log.stream
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* {Stream} Default: `process.stderr`
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The stream where output is written.
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## log.enableColor()
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Force colors to be used on all messages, regardless of the output
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stream.
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## log.disableColor()
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Disable colors on all messages.
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## log.enableProgress()
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Enable the display of log activity spinner and progress bar
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## log.disableProgress()
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Disable the display of a progress bar
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## log.enableUnicode()
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Force the unicode theme to be used for the progress bar.
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## log.disableUnicode()
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Disable the use of unicode in the progress bar.
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## log.setGaugeTemplate(template)
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Set a template for outputting the progress bar. See the [gauge documentation] for details.
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[gauge documentation]: https://npmjs.com/package/gauge
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## log.setGaugeThemeset(themes)
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Select a themeset to pick themes from for the progress bar. See the [gauge documentation] for details.
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## log.pause()
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Stop emitting messages to the stream, but do not drop them.
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## log.resume()
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Emit all buffered messages that were written while paused.
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## log.log(level, prefix, message, ...)
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* `level` {String} The level to emit the message at
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* `prefix` {String} A string prefix. Set to "" to skip.
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* `message...` Arguments to `util.format`
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Emit a log message at the specified level.
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## log\[level](prefix, message, ...)
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For example,
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* log.silly(prefix, message, ...)
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* log.verbose(prefix, message, ...)
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* log.info(prefix, message, ...)
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* log.http(prefix, message, ...)
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* log.warn(prefix, message, ...)
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* log.error(prefix, message, ...)
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Like `log.log(level, prefix, message, ...)`. In this way, each level is
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given a shorthand, so you can do `log.info(prefix, message)`.
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## log.addLevel(level, n, style, disp)
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* `level` {String} Level indicator
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* `n` {Number} The numeric level
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* `style` {Object} Object with fg, bg, inverse, etc.
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* `disp` {String} Optional replacement for `level` in the output.
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Sets up a new level with a shorthand function and so forth.
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Note that if the number is `Infinity`, then setting the level to that
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will cause all log messages to be suppressed. If the number is
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`-Infinity`, then the only way to show it is to enable all log messages.
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## log.newItem(name, todo, weight)
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* `name` {String} Optional; progress item name.
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* `todo` {Number} Optional; total amount of work to be done. Default 0.
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* `weight` {Number} Optional; the weight of this item relative to others. Default 1.
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This adds a new `are-we-there-yet` item tracker to the progress tracker. The
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object returned has the `log[level]` methods but is otherwise an
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`are-we-there-yet` `Tracker` object.
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## log.newStream(name, todo, weight)
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This adds a new `are-we-there-yet` stream tracker to the progress tracker. The
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object returned has the `log[level]` methods but is otherwise an
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`are-we-there-yet` `TrackerStream` object.
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## log.newGroup(name, weight)
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This adds a new `are-we-there-yet` tracker group to the progress tracker. The
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object returned has the `log[level]` methods but is otherwise an
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`are-we-there-yet` `TrackerGroup` object.
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# Events
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Events are all emitted with the message object.
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* `log` Emitted for all messages
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* `log.<level>` Emitted for all messages with the `<level>` level.
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* `<prefix>` Messages with prefixes also emit their prefix as an event.
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# Style Objects
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Style objects can have the following fields:
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* `fg` {String} Color for the foreground text
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* `bg` {String} Color for the background
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* `bold`, `inverse`, `underline` {Boolean} Set the associated property
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* `bell` {Boolean} Make a noise (This is pretty annoying, probably.)
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# Message Objects
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Every log event is emitted with a message object, and the `log.record`
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list contains all of them that have been created. They have the
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following fields:
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* `id` {Number}
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* `level` {String}
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* `prefix` {String}
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* `message` {String} Result of `util.format()`
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* `messageRaw` {Array} Arguments to `util.format()`
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# Blocking TTYs
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We use [`set-blocking`](https://npmjs.com/package/set-blocking) to set
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stderr and stdout blocking if they are tty's and have the setBlocking call.
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This is a work around for an issue in early versions of Node.js 6.x, which
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made stderr and stdout non-blocking on OSX. (They are always blocking
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Windows and were never blocking on Linux.) `npmlog` needs them to be blocking
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so that it can allow output to stdout and stderr to be interlaced.
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