400 lines
15 KiB
Markdown
400 lines
15 KiB
Markdown
gauge
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=====
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A nearly stateless terminal based horizontal gauge / progress bar.
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```javascript
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var Gauge = require("gauge")
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var gauge = new Gauge()
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gauge.show("test", 0.20)
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gauge.pulse("this")
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gauge.hide()
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```
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### CHANGES FROM 1.x
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Gauge 2.x is breaking release, please see the [changelog] for details on
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what's changed if you were previously a user of this module.
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[changelog]: CHANGELOG.md
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### THE GAUGE CLASS
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This is the typical interface to the module– it provides a pretty
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fire-and-forget interface to displaying your status information.
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```
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var Gauge = require("gauge")
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var gauge = new Gauge([stream], [options])
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```
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* **stream** – *(optional, default STDERR)* A stream that progress bar
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updates are to be written to. Gauge honors backpressure and will pause
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most writing if it is indicated.
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* **options** – *(optional)* An option object.
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Constructs a new gauge. Gauges are drawn on a single line, and are not drawn
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if **stream** isn't a tty and a tty isn't explicitly provided.
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If **stream** is a terminal or if you pass in **tty** to **options** then we
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will detect terminal resizes and redraw to fit. We do this by watching for
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`resize` events on the tty. (To work around a bug in verisons of Node prior
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to 2.5.0, we watch for them on stdout if the tty is stderr.) Resizes to
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larger window sizes will be clean, but shrinking the window will always
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result in some cruft.
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**IMPORTANT:** If you prevously were passing in a non-tty stream but you still
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want output (for example, a stream wrapped by the `ansi` module) then you
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need to pass in the **tty** option below, as `gauge` needs access to
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the underlying tty in order to do things like terminal resizes and terminal
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width detection.
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The **options** object can have the following properties, all of which are
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optional:
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* **updateInterval**: How often gauge updates should be drawn, in miliseconds.
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* **fixedFramerate**: Defaults to false on node 0.8, true on everything
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else. When this is true a timer is created to trigger once every
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`updateInterval` ms, when false, updates are printed as soon as they come
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in but updates more often than `updateInterval` are ignored. The reason
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0.8 doesn't have this set to true is that it can't `unref` its timer and
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so it would stop your program from exiting– if you want to use this
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feature with 0.8 just make sure you call `gauge.disable()` before you
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expect your program to exit.
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* **themes**: A themeset to use when selecting the theme to use. Defaults
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to `gauge/themes`, see the [themes] documentation for details.
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* **theme**: Select a theme for use, it can be a:
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* Theme object, in which case the **themes** is not used.
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* The name of a theme, which will be looked up in the current *themes*
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object.
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* A configuration object with any of `hasUnicode`, `hasColor` or
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`platform` keys, which if wlll be used to override our guesses when making
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a default theme selection.
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If no theme is selected then a default is picked using a combination of our
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best guesses at your OS, color support and unicode support.
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* **template**: Describes what you want your gauge to look like. The
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default is what npm uses. Detailed [documentation] is later in this
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document.
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* **hideCursor**: Defaults to true. If true, then the cursor will be hidden
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while the gauge is displayed.
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* **tty**: The tty that you're ultimately writing to. Defaults to the same
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as **stream**. This is used for detecting the width of the terminal and
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resizes. The width used is `tty.columns - 1`. If no tty is available then
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a width of `79` is assumed.
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* **enabled**: Defaults to true if `tty` is a TTY, false otherwise. If true
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the gauge starts enabled. If disabled then all update commands are
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ignored and no gauge will be printed until you call `.enable()`.
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* **Plumbing**: The class to use to actually generate the gauge for
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printing. This defaults to `require('gauge/plumbing')` and ordinarly you
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shouldn't need to override this.
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* **cleanupOnExit**: Defaults to true. Ordinarily we register an exit
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handler to make sure your cursor is turned back on and the progress bar
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erased when your process exits, even if you Ctrl-C out or otherwise exit
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unexpectedly. You can disable this and it won't register the exit handler.
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[has-unicode]: https://www.npmjs.com/package/has-unicode
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[themes]: #themes
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[documentation]: #templates
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#### `gauge.show(section | status, [completed])`
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The first argument is either the section, the name of the current thing
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contributing to progress, or an object with keys like **section**,
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**subsection** & **completed** (or any others you have types for in a custom
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template). If you don't want to update or set any of these you can pass
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`null` and it will be ignored.
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The second argument is the percent completed as a value between 0 and 1.
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Without it, completion is just not updated. You'll also note that completion
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can be passed in as part of a status object as the first argument. If both
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it and the completed argument are passed in, the completed argument wins.
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#### `gauge.hide([cb])`
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Removes the gauge from the terminal. Optionally, callback `cb` after IO has
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had an opportunity to happen (currently this just means after `setImmediate`
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has called back.)
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It turns out this is important when you're pausing the progress bar on one
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filehandle and printing to another– otherwise (with a big enough print) node
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can end up printing the "end progress bar" bits to the progress bar filehandle
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while other stuff is printing to another filehandle. These getting interleaved
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can cause corruption in some terminals.
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#### `gauge.pulse([subsection])`
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* **subsection** – *(optional)* The specific thing that triggered this pulse
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Spins the spinner in the gauge to show output. If **subsection** is
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included then it will be combined with the last name passed to `gauge.show`.
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#### `gauge.disable()`
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Hides the gauge and ignores further calls to `show` or `pulse`.
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#### `gauge.enable()`
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Shows the gauge and resumes updating when `show` or `pulse` is called.
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#### `gauge.isEnabled()`
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Returns true if the gauge is enabled.
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#### `gauge.setThemeset(themes)`
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Change the themeset to select a theme from. The same as the `themes` option
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used in the constructor. The theme will be reselected from this themeset.
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#### `gauge.setTheme(theme)`
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Change the active theme, will be displayed with the next show or pulse. This can be:
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* Theme object, in which case the **themes** is not used.
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* The name of a theme, which will be looked up in the current *themes*
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object.
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* A configuration object with any of `hasUnicode`, `hasColor` or
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`platform` keys, which if wlll be used to override our guesses when making
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a default theme selection.
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If no theme is selected then a default is picked using a combination of our
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best guesses at your OS, color support and unicode support.
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#### `gauge.setTemplate(template)`
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Change the active template, will be displayed with the next show or pulse
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### Tracking Completion
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If you have more than one thing going on that you want to track completion
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of, you may find the related [are-we-there-yet] helpful. It's `change`
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event can be wired up to the `show` method to get a more traditional
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progress bar interface.
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[are-we-there-yet]: https://www.npmjs.com/package/are-we-there-yet
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### THEMES
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```
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var themes = require('gauge/themes')
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// fetch the default color unicode theme for this platform
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var ourTheme = themes({hasUnicode: true, hasColor: true})
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// fetch the default non-color unicode theme for osx
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var ourTheme = themes({hasUnicode: true, hasColor: false, platform: 'darwin'})
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// create a new theme based on the color ascii theme for this platform
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// that brackets the progress bar with arrows
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var ourTheme = themes.newTheme(theme(hasUnicode: false, hasColor: true}), {
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preProgressbar: '→',
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postProgressbar: '←'
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})
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```
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The object returned by `gauge/themes` is an instance of the `ThemeSet` class.
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```
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var ThemeSet = require('gauge/theme-set')
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var themes = new ThemeSet()
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// or
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var themes = require('gauge/themes')
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var mythemes = themes.newThemeset() // creates a new themeset based on the default themes
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```
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#### themes(opts)
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#### themes.getDefault(opts)
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Theme objects are a function that fetches the default theme based on
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platform, unicode and color support.
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Options is an object with the following properties:
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* **hasUnicode** - If true, fetch a unicode theme, if no unicode theme is
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available then a non-unicode theme will be used.
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* **hasColor** - If true, fetch a color theme, if no color theme is
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available a non-color theme will be used.
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* **platform** (optional) - Defaults to `process.platform`. If no
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platform match is available then `fallback` is used instead.
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If no compatible theme can be found then an error will be thrown with a
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`code` of `EMISSINGTHEME`.
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#### themes.addTheme(themeName, themeObj)
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#### themes.addTheme(themeName, [parentTheme], newTheme)
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Adds a named theme to the themeset. You can pass in either a theme object,
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as returned by `themes.newTheme` or the arguments you'd pass to
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`themes.newTheme`.
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#### themes.getThemeNames()
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Return a list of all of the names of the themes in this themeset. Suitable
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for use in `themes.getTheme(…)`.
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#### themes.getTheme(name)
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Returns the theme object from this theme set named `name`.
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If `name` does not exist in this themeset an error will be thrown with
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a `code` of `EMISSINGTHEME`.
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#### themes.setDefault([opts], themeName)
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`opts` is an object with the following properties.
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* **platform** - Defaults to `'fallback'`. If your theme is platform
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specific, specify that here with the platform from `process.platform`, eg,
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`win32`, `darwin`, etc.
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* **hasUnicode** - Defaults to `false`. If your theme uses unicode you
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should set this to true.
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* **hasColor** - Defaults to `false`. If your theme uses color you should
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set this to true.
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`themeName` is the name of the theme (as given to `addTheme`) to use for
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this set of `opts`.
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#### themes.newTheme([parentTheme,] newTheme)
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Create a new theme object based on `parentTheme`. If no `parentTheme` is
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provided then a minimal parentTheme that defines functions for rendering the
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activity indicator (spinner) and progress bar will be defined. (This
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fallback parent is defined in `gauge/base-theme`.)
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newTheme should be a bare object– we'll start by discussing the properties
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defined by the default themes:
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* **preProgressbar** - displayed prior to the progress bar, if the progress
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bar is displayed.
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* **postProgressbar** - displayed after the progress bar, if the progress bar
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is displayed.
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* **progressBarTheme** - The subtheme passed through to the progress bar
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renderer, it's an object with `complete` and `remaining` properties
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that are the strings you want repeated for those sections of the progress
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bar.
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* **activityIndicatorTheme** - The theme for the activity indicator (spinner),
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this can either be a string, in which each character is a different step, or
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an array of strings.
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* **preSubsection** - Displayed as a separator between the `section` and
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`subsection` when the latter is printed.
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More generally, themes can have any value that would be a valid value when rendering
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templates. The properties in the theme are used when their name matches a type in
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the template. Their values can be:
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* **strings & numbers** - They'll be included as is
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* **function (values, theme, width)** - Should return what you want in your output.
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*values* is an object with values provided via `gauge.show`,
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*theme* is the theme specific to this item (see below) or this theme object,
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and *width* is the number of characters wide your result should be.
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There are a couple of special prefixes:
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* **pre** - Is shown prior to the property, if its displayed.
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* **post** - Is shown after the property, if its displayed.
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And one special suffix:
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* **Theme** - Its value is passed to a function-type item as the theme.
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#### themes.addToAllThemes(theme)
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This *mixes-in* `theme` into all themes currently defined. It also adds it
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to the default parent theme for this themeset, so future themes added to
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this themeset will get the values from `theme` by default.
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#### themes.newThemeset()
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Copy the current themeset into a new one. This allows you to easily inherit
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one themeset from another.
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### TEMPLATES
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A template is an array of objects and strings that, after being evaluated,
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will be turned into the gauge line. The default template is:
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```javascript
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[
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{type: 'progressbar', length: 20},
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{type: 'activityIndicator', kerning: 1, length: 1},
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{type: 'section', kerning: 1, default: ''},
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{type: 'subsection', kerning: 1, default: ''}
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]
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```
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The various template elements can either be **plain strings**, in which case they will
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be be included verbatum in the output, or objects with the following properties:
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* *type* can be any of the following plus any keys you pass into `gauge.show` plus
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any keys you have on a custom theme.
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* `section` – What big thing you're working on now.
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* `subsection` – What component of that thing is currently working.
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* `activityIndicator` – Shows a spinner using the `activityIndicatorTheme`
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from your active theme.
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* `progressbar` – A progress bar representing your current `completed`
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using the `progressbarTheme` from your active theme.
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* *kerning* – Number of spaces that must be between this item and other
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items, if this item is displayed at all.
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* *maxLength* – The maximum length for this element. If its value is longer it
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will be truncated.
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* *minLength* – The minimum length for this element. If its value is shorter it
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will be padded according to the *align* value.
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* *align* – (Default: left) Possible values "left", "right" and "center". Works
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as you'd expect from word processors.
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* *length* – Provides a single value for both *minLength* and *maxLength*. If both
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*length* and *minLength or *maxLength* are specifed then the latter take precedence.
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* *value* – A literal value to use for this template item.
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* *default* – A default value to use for this template item if a value
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wasn't otherwise passed in.
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### PLUMBING
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This is the super simple, assume nothing, do no magic internals used by gauge to
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implement its ordinary interface.
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```
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var Plumbing = require('gauge/plumbing')
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var gauge = new Plumbing(theme, template, width)
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```
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* **theme**: The theme to use.
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* **template**: The template to use.
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* **width**: How wide your gauge should be
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#### `gauge.setTheme(theme)`
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Change the active theme.
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#### `gauge.setTemplate(template)`
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Change the active template.
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#### `gauge.setWidth(width)`
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Change the width to render at.
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#### `gauge.hide()`
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Return the string necessary to hide the progress bar
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#### `gauge.hideCursor()`
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Return a string to hide the cursor.
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#### `gauge.showCursor()`
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Return a string to show the cursor.
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#### `gauge.show(status)`
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Using `status` for values, render the provided template with the theme and return
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a string that is suitable for printing to update the gauge.
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