documentation/api.md

   1 <!--
   2 This is part of the VimFx documentation.
   3 Copyright Simon Lydell 2015.
   4 See the file README.md for copying conditions.
   5 -->
   6
   7 # Public API
   8
   9 VimFx has a public API. It is intended to be used by:
  10
  11 - Users who prefer to configure things using text files.
  12 - Users who would like to add custom commands.
  13 - Users who would like to set [special options].
  14 - Users who would like to make site-specific customizations.
  15 - Extension authors who would like to extend VimFx.
  16
  17 VimFx users who use the public API should write a so-called [config file].
  18
  19
  20 ## Getting the API
  21
  22 ```js
  23 let {classes: Cc, interfaces: Ci, utils: Cu} = Components
  24 Cu.import('resource://gre/modules/Services.jsm')
  25 let apiPref = 'extensions.VimFx.api_url'
  26 let apiUrl = Services.prefs.getComplexValue(apiPref, Ci.nsISupportsString).data
  27 Cu.import(apiUrl, {}).getAPI(vimfx => {
  28
  29   // Do things with the `vimfx` object here.
  30
  31 })
  32 ```
  33
  34 You might also want to take a look at the [config file bootstrap.js
  35 example][bootstrap.js].
  36
  37 Note that the callback passed to `getAPI` is called once every time VimFx starts
  38 up, not once per Firefox session! This means that if you update VimFx (or
  39 disable and then enable it), the callback is re-run with the new version.
  40
  41
  42 ## API
  43
  44 The following sub-sections assume that you store VimFx’s public API in a
  45 variable called `vimfx`.
  46
  47 ### `vimfx.get(pref)`, `vimfx.getDefault(pref)` and `vimfx.set(pref, value)`
  48
  49 Gets or sets the (default) value of the VimFx pref `pref`.
  50
  51 You can see all prefs in [defaults.coffee], or by opening [about:config] and
  52 filtering by `extensions.vimfx`. Note that you can also access the [special
  53 options], which may not be accessed in [about:config], using `vimfx.get()` and
  54 `vimfx.set()`—in fact, this is the _only_ way of accessing those options.
  55
  56 #### `vimfx.get(pref)`
  57
  58 Gets the value of the VimFx pref `pref`.
  59
  60 ```js
  61 // Get the value of the Hint chars option:
  62 vimfx.get('hint_chars')
  63 // Get all keyboard shortcuts (as a string) for the `f` command:
  64 vimfx.get('mode.normal.follow')
  65 ```
  66
  67 #### `vimfx.getDefault(pref)`
  68
  69 Gets the default value of the VimFx pref `pref`.
  70
  71 Useful when you wish to extend a default, rather than replacing it. See below.
  72
  73 #### `vimfx.set(pref, value)`
  74
  75 Sets the value of the VimFx pref `pref` to `value`.
  76
  77 ```js
  78 // Set the value of the Hint chars option:
  79 vimfx.set('hint_chars', 'abcdefghijklmnopqrstuvwxyz')
  80 // Add yet a keyboard shortcut for the `f` command:
  81 vimfx.set('mode.normal.follow', vimfx.getDefault('mode.normal.follow') + '  e')
  82 ```
  83
  84 When extending a pref (as in the second example above), be sure to use
  85 `vimfx.getDefault` rather than `vimfx.get`. Otherwise you get a multiplying
  86 effect. In the above example, after starting Firefox a few times the pref would
  87 be `f  e  e  e  e`. Also, if you find that example very verbose: Remember that
  88 you’re using a programming language! Write a small helper function that suits
  89 your needs.
  90
  91 Note: If you produce conflicting keyboard shortcuts, the order of your code does
  92 not matter. The command that comes first in VimFx’s settings page in the Add-ons
  93 Manager (and in the help dialog) gets the shortcut; the other one(s) do(es) not.
  94 See the notes about order in [mode object], [category object] and [command
  95 object] for more information about order.
  96
  97 ```js
  98 // Even though we set the shortcut for focusing the search bar last, the command
  99 // for focusing the location bar “wins”, because it comes first in VimFx’s
 100 // settings page in the Add-ons Manager.
 101 vimfx.set('mode.normal.focus_location_bar', 'ö')
 102 vimfx.set('mode.normal.focus_search_bar', 'ö')
 103
 104 // Swapping their orders also swaps the “winner”.
 105 let {commands} = vimfx.modes.normal
 106 ;[commands.focus_location_bar.order, commands.focus_search_bar.order] =
 107   [commands.focus_search_bar.order, commands.focus_location_bar.order]
 108 ```
 109
 110 ### `vimfx.addCommand(options, fn)`
 111
 112 Creates a new command.
 113
 114 **Note:** This should only be used by config file users, not by extension
 115 authors who wish to extend VimFx. They should add commands manually to
 116 [`vimfx.modes`] instead.
 117
 118 `options`:
 119
 120 - name: `String`. The name used when accessing the command via
 121   `vimfx.modes[options.mode].commands[options.name]`. It is also used for the
 122   pref used to store the shortcuts for the command:
 123   `` `custom.mode.${options.mode}.${options.name}` ``.
 124 - description: `String`. Shown in the help dialog and VimFx’s settings page in
 125   the Add-ons Manager.
 126 - mode: `String`. Defaults to `'normal'`. The mode to add the command to. The
 127   value has to be one of the keys of [`vimfx.modes`].
 128 - category: `String`. Defaults to `'misc'` for Normal mode and `''`
 129   (uncategorized) otherwise. The category to add the command to. The
 130   value has to be one of the keys of [`vimfx.get('categories')`][categories].
 131 - order: `Number`. Defaults to putting the command at the end of the category.
 132   The first of the default commands has the order `100` and then they increase
 133   by `100` per command. This allows to put new commands between two already
 134   existing ones.
 135
 136 `fn` is called when the command is activated. See the [onInput] documentation
 137 below for more information.
 138
 139 Note that you have to give the new command a shortcut in VimFx’s settings page
 140 in the Add-ons Manager or set one using `vimfx.set()` to able to use the new
 141 command.
 142
 143 ```js
 144 vimfx.addCommand({
 145   name: 'hello',
 146   description: 'Log Hello World',
 147 }, => {
 148   console.log('Hello World!')
 149 })
 150 // Optional:
 151 vimfx.set('custom.mode.normal.hello', 'gö')
 152 ```
 153
 154 ### `vimfx.addOptionOverrides(...rules)` and `vimfx.addKeyOverrides(...rules)`
 155
 156 These methods take any number of arguments. Each argument is a rule. The rules
 157 are added in order. The methods may be run multiple times.
 158
 159 A rule is an `Array` of length 2:
 160
 161 1. The first item is a function that returns `true` if the rule should be
 162    applied and `false` if not. This is called the matching function.
 163 2. The second item is the value that should be used if the rule is applied. This
 164    is called the override.
 165
 166 The rules are tried in the same order they were added. When a matching rule is
 167 found it is applied. No more rules will be applied.
 168
 169 #### `vimfx.addOptionOverrides(...rules)`
 170
 171 The rules are matched any time the value of a VimFx pref is needed.
 172
 173 The matching function receives a [location object].
 174
 175 The override is an object whose keys are VimFx pref names and whose values
 176 override the pref in question. The values should be formatted as in an [options
 177 object].
 178
 179 ```js
 180 vimfx.addOptionOverrides(
 181   [ ({hostname, pathname, hash}) =>
 182     `${hostname}${pathname}${hash}` === 'google.com/',
 183     {prevent_autofocus: false}
 184   ]
 185 )
 186 ```
 187
 188 #### `vimfx.addKeyOverrides(...rules)`
 189
 190 The rules are matched any time you press a key that is not part of the tail of a
 191 multi-key shortcut.
 192
 193 The matching function receives a [location object] as well as the current
 194 mode name (one of the keys of [`vimfx.modes`]).
 195
 196 The override is an array of keys which should not activate VimFx commands but be
 197 sent to the page.
 198
 199 This allows to disable commands on specific sites. To _add_ commands on specific
 200 sites, add them globally and then disable them on all _other_ sites.
 201
 202 ```js
 203 vimfx.addKeyOverrides(
 204   [ location => location.hostname === 'facebook.com',
 205     ['j', 'k']
 206   ]
 207 )
 208 ```
 209
 210 ### `vimfx.on(eventName, listener)`
 211
 212 Runs `listener(data)` when `eventName` is fired.
 213
 214 #### The `locationChange` event
 215
 216 Occurs when opening a new tab, navigating to a new URL or refreshing the page,
 217 causing a full page load. The data passed to listeners is an object with the
 218 following properties:
 219
 220 - vim: The current [vim object].
 221 - location: A [location object].
 222
 223 This can be used to enter a different mode by default on some pages (which can
 224 be used to replace the blacklist option).
 225
 226 ```js
 227 vimfx.on('locationChange', ({vim, location}) => {
 228   if (location.hostname === 'example.com') {
 229     vim.enterMode('ignore')
 230   }
 231 })
 232 ```
 233
 234 #### The `notification` and `hideNotification` events
 235
 236 The `notification` event occurs when `vim.notify(message)` is called, and means
 237 that `message` should be displayed to the user.
 238
 239 The `hideNotification` event occurs when the `vim.hideNotification()` is called,
 240 and means that the current notification is requested to be hidden.
 241
 242 The data passed to listeners is an object with the following properties:
 243
 244 - vim: The current [vim object].
 245 - message: The message that should be notified. Only for the `notification`
 246   event.
 247
 248 Both of these events are emitted even if the [`notifications_enabled`] option is
 249 disabled, allowing you to display notifications in any way you want.
 250
 251 #### The `modeChange` event
 252
 253 Occurs whenever the current mode in any tab changes. The initial entering of the
 254 default mode in new tabs also counts as a mode change. The data passed to
 255 listeners is the current [vim object].
 256
 257 ```js
 258 vimfx.on('modeChange', vim => {
 259   let mode = vimfx.modes[vim.mode].name()
 260   vim.notify(`Entering mode: ${mode}`)
 261 })
 262 ```
 263
 264 #### The `TabSelect` event
 265
 266 Occurs whenever any tab in any window is selected. This is also fired when
 267 Firefox starts for the currently selected tab. The data passed to listeners is
 268 the `event` object passed to the standard Firefox [TabSelect] event.
 269
 270 ### The `modeDisplayChange` event
 271
 272 This is basically a combination of the `modeChange` and the `TabSelect` events.
 273 The event is useful for knowing when to update UI showing the current mode. (In
 274 fact, VimFx itself uses it to update the toolbar [button]!) The data passed to
 275 listeners is the current [vim object].
 276
 277 You can also highlight the current mode using [styling].
 278
 279
 280 ### `vimfx.modes`
 281
 282 An object whose keys are mode names and whose values are [mode object]s.
 283
 284 This is a very low-level part of the API. It allows to:
 285
 286 - Access all commands and run them. This is the only thing that a config file
 287   user needs it for.
 288
 289   ```js
 290     let {commands} = vimfx.modes.normal
 291     // Inside a custom command:
 292     commands.tab_new.run(args)
 293   ```
 294
 295 - Adding new commands. This is intended to be used by extension authors who wish
 296   to extend VimFx, not config file users. They should use the
 297   `vimfx.addCommand()` helper instead.
 298
 299   ```js
 300   vimfx.modes.normal.commands.new_command = {
 301     pref: 'extensions.my_extension.mode.normal.new_command',
 302     category: 'misc',
 303     order: 10000,
 304     description: () => translate('mode.normal.new_command'),
 305     run: args => console.log('New command! args:', args)
 306   }
 307   ```
 308
 309 - Adding new modes. This is intended to be used by extension authors who wish to
 310   extend VimFx, not config file users.
 311
 312   ```js
 313   vimfx.modes.new_mode = {
 314     name: () => translate('mode.new_mode'),
 315     order: 10000,
 316     commands: {},
 317     onEnter(args) {},
 318     onLeave(args) {},
 319     onInput(args, match) {
 320       if (match.type === 'full') {
 321         match.command.run(args)
 322       }
 323       return (match.type !== 'none')
 324     },
 325   }
 326   ```
 327
 328 Have a look at [modes.coffee] and [commands.coffee] for more information.
 329
 330 ### `vimfx.get('categories')`
 331
 332 An object whose keys are category names and whose values are [category object]s.
 333
 334 ```js
 335 let categories = vimfx.get('categories')
 336
 337 // Add a new category.
 338 categories.custom = {
 339   name: () => 'Custom commands',
 340   order: 10000,
 341 }
 342
 343 // Swap the order of the Location and Tabs categories.
 344 ;[commands.focus_location_bar.order, categories.tabs.order] =
 345   [categories.tabs.order, commands.focus_location_bar.order]
 346 ```
 347
 348 ### Mode object
 349
 350 A mode is an object with the follwing properties:
 351
 352 - name(): `Function`. Returns a human readable name of the mode used in the help
 353   dialog and VimFx’s settings page in the Add-ons Manager.
 354 - order: `Number`. The first of the default modes has the order `100` and then
 355   they increase by `100` per mode. This allows to put new modes between two
 356   already existing ones.
 357 - commands: `Object`. The keys are command names and the values are [command
 358   object]s.
 359 - onEnter(data, ...args): `Function`. Called when the mode is entered.
 360 - onLeave(data): `Function`. Called when the mode is left.
 361 - onInput(data, match): `Function`. Called when a key is pressed.
 362
 363 #### onEnter, onLeave and onInput
 364
 365 These methods are called with an object (called `data` above) with the following
 366 properties:
 367
 368 - vim: The current [vim object].
 369 - storage: An object unique to the current [vim object] and to the current mode.
 370   Allows to share things between commands of the same mode by getting and
 371   setting keys on it.
 372
 373 ##### onEnter
 374
 375 This method is called with an object as mentioned above, and after that there
 376 may be any number of arguments (`args` in `vim.enterMode(modeName, ...args)`)
 377 that the mode is free to do whatever it wants with.
 378
 379 Whatever is returned from `onEnter` will be returned from
 380 `vim.enterMode(modeName, ...args)`.
 381
 382 ##### onInput
 383
 384 The object passed to this method (see above) also has the following properties:
 385
 386 - uiEvent: `Event` or `false`. The keydown event object if the event occured in
 387   the browser UI, `false` otherwise (if the event occured in web page content).
 388 - count: `Number`. The count for the command. `undefined` if no count. (This is
 389   simply a copy of `match.count`. `match` is defined below.)
 390
 391 The above object should be passed to commands when running them. The mode is
 392 free to do whatever it wants with the return value (if any) of the commands it
 393 runs.
 394
 395 It also receives a [match object] as the second argument.
 396
 397 `onInput` should return `true` if the current keypress should not be passed on
 398 to the browser and web pages, and `false` otherwise.
 399
 400 ### Category object
 401
 402 A category is an object with the follwing properties:
 403
 404 - name(): `Function`. Returns a human readable name of the category used in the
 405   help dialog and VimFx’s settings page in the Add-ons Manager. Config file
 406   users adding custom categories could simply return a string; extension authors
 407   are encouraged to look up the name from a locale file.
 408 - order: `Number`. The first of the default categories is the “uncategorized”
 409   category. It has the order `100` and then they increase by `100` per category.
 410   This allows to put new categories between two already existing ones.
 411
 412 ### Command object
 413
 414 A command is an object with the following properties:
 415
 416 - pref: `String`. The pref used to store the shortcuts for the command.
 417 - run(args): `Function`. Called when the command is activated.
 418 - description(): `Function`. Returns a description of the command (as a string),
 419   shown in the help dialog and VimFx’s settings page in the Add-ons Manager.
 420 - category: `String`. The category to add the command to. The value has to be
 421   one of the keys of [`vimfx.get('categories')`][categories].
 422 - order: `Number`. The first of the default commands has the order `100` and
 423   then they increase by `100` per command. This allows to put new commands
 424   between two already existing ones.
 425
 426 ### Match object
 427
 428 A `match` object has the following properties:
 429
 430 - type: `String`. It has one of the following values:
 431
 432   - `'full'`: The current keypress, together with previous keypresses, fully
 433     matches a command shortcut.
 434   - `'partial'`: The current keypress, together with previous keypresses,
 435     partially matches a command shortcut.
 436   - `'count'`: The current keypress is not part of a command shortcut, but is a
 437     digit and contributes to the count of a future matched command.
 438   - `'none'`: The current keypress is not part of a command shortcut and does
 439     not contribute to a count.
 440
 441 - focus: `String` or `null`. The type of currently focused _element_ plus
 442   current pressed _key_ combo. You might not want to run commands and suppress
 443   the event if this value is anything other than null. It has one of the
 444   following values, depending on what kind of _element_ is focused and which
 445   _key_ was pressed:
 446
 447   - `'editable'`: element: a text input or a `contenteditable` element.
 448     key: any pressed key.
 449   - `'activatable'`: element: an “activatable” element (link or button).
 450     key: see the [`activatable_element_keys`] option.
 451   - `'adjustable'`: element: an “adjustable” element (form control or video
 452     player). key: see the [`adjustable_element_keys`] option.
 453   - `'other'`: element: some other kind of element that can receive keystrokes,
 454     for example an element in fullscreen mode. key: any pressed key.
 455
 456   If none of the above criteria is met, the value is `null`, which means that
 457   the currently focused element does not appear to respond to keystrokes in any
 458   special way.
 459
 460 - command: `null` unless `type` is `'full'`. Then it is the matched command (a
 461   [command object]).
 462
 463   The matched command should usually be run at this point. It is suitable to
 464   pass on the object passed to [onInput] to the command. Some modes might choose
 465   to add extra properties to the object first. (That is favored over passing
 466   several arguments, since it makes it easier for the command to in turn pass
 467   the same data it got on to another command, if needed.)
 468
 469   Usually the return value of the command isn’t used, but that’s up to the mode.
 470
 471 - count: `Number`. The count for the command. `undefined` if no count.
 472
 473 - specialKeys: `Object`. The keys may be any of the following:
 474
 475   - `<force>`
 476   - `<late>`
 477
 478   If a key exists, its value is always `true`. The keys that exist indicate the
 479   [special keys] for the sequence used for the matched command (if any).
 480
 481 - keyStr: `String`. The current keypress represented as a string.
 482
 483 - unmodifiedKey: `String`. `keyStr` without modifiers.
 484
 485 - toplevel: `Boolean`. Whether or not the match was a toplevel match in the
 486   shortcut key tree. This is `true` unless the match is part of the tail of a
 487   multi-key shortcut.
 488
 489 ### Vim object
 490
 491 There is one `vim` object per tab.
 492
 493 A `vim` object has the following properties:
 494
 495 - window: [`Window`]. The current Firefox window object. Most commands
 496   interacting with Firefox’s UI use this.
 497
 498 - browser: [`Browser`]. The `browser` that this vim object handles.
 499
 500 - options: `Object`. Provides access to all of VimFx’s options. It is an
 501   [options object].
 502
 503 - mode: `String`. The current mode name.
 504
 505 - enterMode(modeName, ...args): `Function`. Enter mode `modeName`, passing
 506   `...args` to the mode. It is up to every mode to do whatever it wants to with
 507   `...args`. If `modeName` was already the current mode, nothing is done and
 508   `undefined` is returned. Otherwise it us up to the mode to return whatever it
 509   wants to.
 510
 511 - isUIEvent(event): `Function`. Returns `true` if `event` occurred in the
 512   browser UI, and `false` otherwise (if it occurred in web page content).
 513
 514 - notify(message): `Function`. Display a notification with the text `message`.
 515
 516 - hideNotification(): `Function`. Hide the current notification (if any).
 517
 518 - markPageInteraction(): `Function`. Marks that the user has interacted with the
 519   page. After that [autofocus prevention] is not done anymore. Commands
 520   interacting with web page content might want to do this.
 521
 522 **Warning:** There are also properties starting with an underscore on `vim`
 523 objects. They are private, and not supposed to be used outside of VimFx’s own
 524 source code. They may change at any time.
 525
 526 ### Options object
 527
 528 An `options` object provides access to all of VimFx’s options. It is an object
 529 whose keys are VimFx pref names.
 530
 531 Note that the values are not just simply `vimfx.get(pref)` for the `pref` in
 532 question; they are _parsed_ (`parse(vimfx.get(pref))`):
 533
 534 - Space-separated prefs are parsed into arrays of strings.
 535
 536 - `black_list` and `{prev,next}_patterns` are parsed into arrays of regular
 537   expressions.
 538
 539 (See [parse-prefs.coffee] for all details.)
 540
 541 Any [option overrides] are automatically taken into account when getting an
 542 option value.
 543
 544 The [special options] are also available on this object.
 545
 546
 547 ### Location object
 548
 549 A location object is very similar to [`window.location`] in web pages.
 550 Technically, it is a [`URL`] instance. You can experient with the current
 551 location object by opening the [web console] and entering `location`.
 552
 553
 554 ## Stability
 555
 556 The public API is currently **experimental** and therefore **unstable.** Things
 557 might break with new VimFx versions. However, no breaking changes are planned,
 558 and will be avoided if feasible.
 559
 560 As soon as VimFx 1.0.0 (which does not seem to be too far away) is released
 561 backwards compatibility will be a priority and won’t be broken until VimFx
 562 2.0.0.
 563
 564 [option overrides]: #vimfxaddoptionoverridesrules
 565 [categories]: #vimfxgetcategories
 566 [`vimfx.modes`]: #vimfxmodes
 567 [onInput]: #oninput
 568 [mode object]: #mode-object
 569 [category object]: #category-object
 570 [command object]: #command-object
 571 [match object]: #match-object
 572 [vim object]: #vim-object
 573 [options object]: #options-object
 574 [location object]: #location-object
 575
 576 [blacklisted]: options.md#blacklist
 577 [special options]: options.md#special-options
 578 [config file]: config-file.md
 579 [bootstrap.js]: config-file.md#bootstrapjs
 580 [autofocus prevention]: options.md#prevent-autofocus
 581 [`activatable_element_keys`]: options.md#activatable_element_keys
 582 [`adjustable_element_keys`]: options.md#adjustable_element_keys
 583 [`notifications_enabled`]: options.md#notifications_enabled
 584
 585 [button]: button.md
 586 [special keys]: shortcuts.md#special-keys
 587 [styling]: styling.md
 588
 589 [defaults.coffee]: ../extension/lib/defaults.coffee
 590 [parse-prefs.coffee]: ../extension/lib/parse-prefs.coffee
 591 [modes.coffee]: ../extension/lib/modes.coffee
 592 [commands.coffee]: ../extension/lib/commands.coffee
 593 [vim.coffee]: ../extension/lib/vim.coffee
 594
 595 [`Window`]: https://developer.mozilla.org/en-US/docs/Web/API/Window
 596 [`Browser`]: https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XUL/browser
 597 [`window.location`]: https://developer.mozilla.org/en-US/docs/Web/API/Location
 598 [`URL`]: https://developer.mozilla.org/en-US/docs/Web/API/URL
 599 [TabSelect]: https://developer.mozilla.org/en-US/docs/Web/Events/TabSelect
 600 [web console]: https://developer.mozilla.org/en-US/docs/Tools/Web_Console
 601 [about:config]: http://kb.mozillazine.org/About:config