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 `modeChange` event
 235
 236 Occurs whenever the current mode in any tab changes. The initial entering of the
 237 default mode in new tabs also counts as a mode change. The data passed to
 238 listeners is the current [vim object].
 239
 240 ```js
 241 vimfx.on('modeChange', vim => {
 242   let mode = vimfx.modes[vim.mode].name()
 243   vim.notify(`Entering mode: ${mode}`)
 244 })
 245 ```
 246
 247 #### The `TabSelect` event
 248
 249 Occurs whenever any tab in any window is selected. This is also fired when
 250 Firefox starts for the currently selected tab. The data passed to listeners is
 251 the `event` object passed to the standard Firefox [TabSelect] event.
 252
 253 ### The `modeDisplayChange` event
 254
 255 This is basically a combination of the `modeChange` and the `TabSelect` events.
 256 The event is useful for knowing when to update UI showing the current mode. (In
 257 fact, VimFx itself uses it to update the toolbar [button]!) The data passed to
 258 listeners is the current [vim object].
 259
 260 You can also highlight the current mode using [styling].
 261
 262
 263 ### `vimfx.modes`
 264
 265 An object whose keys are mode names and whose values are [mode object]s.
 266
 267 This is a very low-level part of the API. It allows to:
 268
 269 - Access all commands and run them. This is the only thing that a config file
 270   user needs it for.
 271
 272   ```js
 273     let {commands} = vimfx.modes.normal
 274     // Inside a custom command:
 275     commands.tab_new.run(args)
 276   ```
 277
 278 - Adding new commands. This is intended to be used by extension authors who wish
 279   to extend VimFx, not config file users. They should use the
 280   `vimfx.addCommand()` helper instead.
 281
 282   ```js
 283   vimfx.modes.normal.commands.new_command = {
 284     pref: 'extensions.my_extension.mode.normal.new_command',
 285     category: 'misc',
 286     order: 10000,
 287     description: () => translate('mode.normal.new_command'),
 288     run: args => console.log('New command! args:', args)
 289   }
 290   ```
 291
 292 - Adding new modes. This is intended to be used by extension authors who wish to
 293   extend VimFx, not config file users.
 294
 295   ```js
 296   vimfx.modes.new_mode = {
 297     name: () => translate('mode.new_mode'),
 298     order: 10000,
 299     commands: {},
 300     onEnter(args) {},
 301     onLeave(args) {},
 302     onInput(args, match) {
 303       if (match.type === 'full') {
 304         match.command.run(args)
 305       }
 306       return (match.type !== 'none')
 307     },
 308   }
 309   ```
 310
 311 Have a look at [modes.coffee] and [commands.coffee] for more information.
 312
 313 ### `vimfx.get('categories')`
 314
 315 An object whose keys are category names and whose values are [category object]s.
 316
 317 ```js
 318 let categories = vimfx.get('categories')
 319
 320 // Add a new category.
 321 categories.custom = {
 322   name: () => 'Custom commands',
 323   order: 10000,
 324 }
 325
 326 // Swap the order of the Location and Tabs categories.
 327 ;[commands.focus_location_bar.order, categories.tabs.order] =
 328   [categories.tabs.order, commands.focus_location_bar.order]
 329 ```
 330
 331 ### Mode object
 332
 333 A mode is an object with the follwing properties:
 334
 335 - name(): `Function`. Returns a human readable name of the mode used in the help
 336   dialog and VimFx’s settings page in the Add-ons Manager.
 337 - order: `Number`. The first of the default modes has the order `100` and then
 338   they increase by `100` per mode. This allows to put new modes between two
 339   already existing ones.
 340 - commands: `Object`. The keys are command names and the values are [command
 341   object]s.
 342 - onEnter(data, ...args): `Function`. Called when the mode is entered.
 343 - onLeave(data): `Function`. Called when the mode is left.
 344 - onInput(data, match): `Function`. Called when a key is pressed.
 345
 346 #### onEnter, onLeave and onInput
 347
 348 These methods are called with an object (called `data` above) with the following
 349 properties:
 350
 351 - vim: The current [vim object].
 352 - storage: An object unique to the current [vim object] and to the current mode.
 353   Allows to share things between commands of the same mode by getting and
 354   setting keys on it.
 355
 356 ##### onEnter
 357
 358 This method is called with an object as mentioned above, and after that there
 359 may be any number of arguments (`args` in `vim.enterMode(modeName, ...args)`)
 360 that the mode is free to do whatever it wants with.
 361
 362 Whatever is returned from `onEnter` will be returned from
 363 `vim.enterMode(modeName, ...args)`.
 364
 365 ##### onInput
 366
 367 The object passed to this method (see above) also has the following properties:
 368
 369 - uiEvent: `Event` or `false`. The keydown event object if the event occured in
 370   the browser UI, `false` otherwise (if the event occured in web page content).
 371 - count: `Number`. The count for the command. `undefined` if no count. (This is
 372   simply a copy of `match.count`. `match` is defined below.)
 373
 374 The above object should be passed to commands when running them. The mode is
 375 free to do whatever it wants with the return value (if any) of the commands it
 376 runs.
 377
 378 It also receives a [match object] as the second argument.
 379
 380 `onInput` should return `true` if the current keypress should not be passed on
 381 to the browser and web pages, and `false` otherwise.
 382
 383 ### Category object
 384
 385 A category is an object with the follwing properties:
 386
 387 - name(): `Function`. Returns a human readable name of the category used in the
 388   help dialog and VimFx’s settings page in the Add-ons Manager. Config file
 389   users adding custom categories could simply return a string; extension authors
 390   are encouraged to look up the name from a locale file.
 391 - order: `Number`. The first of the default categories is the “uncategorized”
 392   category. It has the order `100` and then they increase by `100` per category.
 393   This allows to put new categories between two already existing ones.
 394
 395 ### Command object
 396
 397 A command is an object with the following properties:
 398
 399 - pref: `String`. The pref used to store the shortcuts for the command.
 400 - run(args): `Function`. Called when the command is activated.
 401 - description(): `Function`. Returns a description of the command (as a string),
 402   shown in the help dialog and VimFx’s settings page in the Add-ons Manager.
 403 - category: `String`. The category to add the command to. The value has to be
 404   one of the keys of [`vimfx.get('categories')`][categories].
 405 - order: `Number`. The first of the default commands has the order `100` and
 406   then they increase by `100` per command. This allows to put new commands
 407   between two already existing ones.
 408
 409 ### Match object
 410
 411 A `match` object has the following properties:
 412
 413 - type: `String`. It has one of the following values:
 414
 415   - `'full'`: The current keypress, together with previous keypresses, fully
 416     matches a command shortcut.
 417   - `'partial'`: The current keypress, together with previous keypresses,
 418     partially matches a command shortcut.
 419   - `'count'`: The current keypress is not part of a command shortcut, but is a
 420     digit and contributes to the count of a future matched command.
 421   - `'none'`: The current keypress is not part of a command shortcut and does
 422     not contribute to a count.
 423
 424 - focus: `String` or `null`. The type of currently focused _element_ plus
 425   current pressed _key_ combo. You might not want to run commands and suppress
 426   the event if this value is anything other than null. It has one of the
 427   following values, depending on what kind of _element_ is focused and which
 428   _key_ was pressed:
 429
 430   - `'editable'`: element: a text input or a `contenteditable` element.
 431     key: any pressed key.
 432   - `'activatable'`: element: an “activatable” element (link or button).
 433     key: see the [`activatable_element_keys`] option.
 434   - `'adjustable'`: element: an “adjustable” element (form control or video
 435     player). key: see the [`adjustable_element_keys`] option.
 436   - `'other'`: element: some other kind of element that can receive keystrokes,
 437     for example an element in fullscreen mode. key: any pressed key.
 438
 439   If none of the above criteria is met, the value is `null`, which means that
 440   the currently focused element does not appear to respond to keystrokes in any
 441   special way.
 442
 443 - command: `null` unless `type` is `'full'`. Then it is the matched command (a
 444   [command object]).
 445
 446   The matched command should usually be run at this point. It is suitable to
 447   pass on the object passed to [onInput] to the command. Some modes might choose
 448   to add extra properties to the object first. (That is favored over passing
 449   several arguments, since it makes it easier for the command to in turn pass
 450   the same data it got on to another command, if needed.)
 451
 452   Usually the return value of the command isn’t used, but that’s up to the mode.
 453
 454 - count: `Number`. The count for the command. `undefined` if no count.
 455
 456 - specialKeys: `Object`. The keys may be any of the following:
 457
 458   - `<force>`
 459   - `<late>`
 460
 461   If a key exists, its value is always `true`. The keys that exist indicate the
 462   [special keys] for the sequence used for the matched command (if any).
 463
 464 - keyStr: `String`. The current keypress represented as a string.
 465
 466 - unmodifiedKey: `String`. `keyStr` without modifiers.
 467
 468 - toplevel: `Boolean`. Whether or not the match was a toplevel match in the
 469   shortcut key tree. This is `true` unless the match is part of the tail of a
 470   multi-key shortcut.
 471
 472 ### Vim object
 473
 474 There is one `vim` object per tab.
 475
 476 A `vim` object has the following properties:
 477
 478 - window: [`Window`]. The current Firefox window object. Most commands
 479   interacting with Firefox’s UI use this.
 480
 481 - browser: [`Browser`]. The `browser` that this vim object handles.
 482
 483 - options: `Object`. Provides access to all of VimFx’s options. It is an
 484   [options object].
 485
 486 - mode: `String`. The current mode name.
 487
 488 - enterMode(modeName, ...args): `Function`. Enter mode `modeName`, passing
 489   `...args` to the mode. It is up to every mode to do whatever it wants to with
 490   `...args`. If `modeName` was already the current mode, nothing is done and
 491   `undefined` is returned. Otherwise it us up to the mode to return whatever it
 492   wants to.
 493
 494 - isUIEvent(event): `Function`. Returns `true` if `event` occurred in the
 495   browser UI, and `false` otherwise (if it occurred in web page content).
 496
 497 - notify(title, options = {}): `Function`. Display a notification with the title
 498   `title` (a `String`). If you need more text than a title, use `options.body`.
 499   See [`Notification`] for more information.
 500
 501 - markPageInteraction(): `Function`. Marks that the user has interacted with the
 502   page. After that [autofocus prevention] is not done anymore. Commands
 503   interacting with web page content might want to do this.
 504
 505 **Warning:** There are also properties starting with an underscore on `vim`
 506 objects. They are private, and not supposed to be used outside of VimFx’s own
 507 source code. They may change at any time.
 508
 509 ### Options object
 510
 511 An `options` object provides access to all of VimFx’s options. It is an object
 512 whose keys are VimFx pref names.
 513
 514 Note that the values are not just simply `vimfx.get(pref)` for the `pref` in
 515 question; they are _parsed_ (`parse(vimfx.get(pref))`):
 516
 517 - Space-separated prefs are parsed into arrays of strings.
 518
 519 - `black_list` and `{prev,next}_patterns` are parsed into arrays of regular
 520   expressions.
 521
 522 (See [parse-prefs.coffee] for all details.)
 523
 524 Any [option overrides] are automatically taken into account when getting an
 525 option value.
 526
 527 The [special options] are also available on this object.
 528
 529
 530 ### Location object
 531
 532 A location object is very similar to [`window.location`] in web pages.
 533 Technically, it is a [`URL`] instance. You can experient with the current
 534 location object by opening the [web console] and entering `location`.
 535
 536
 537 ## Stability
 538
 539 The public API is currently **experimental** and therefore **unstable.** Things
 540 might break with new VimFx versions. However, no breaking changes are planned,
 541 and will be avoided if feasible.
 542
 543 As soon as VimFx 1.0.0 (which does not seem to be too far away) is released
 544 backwards compatibility will be a priority and won’t be broken until VimFx
 545 2.0.0.
 546
 547 [option overrides]: #vimfxaddoptionoverridesrules
 548 [categories]: #vimfxgetcategories
 549 [`vimfx.modes`]: #vimfxmodes
 550 [onInput]: #oninput
 551 [mode object]: #mode-object
 552 [category object]: #category-object
 553 [command object]: #command-object
 554 [match object]: #match-object
 555 [vim object]: #vim-object
 556 [options object]: #options-object
 557 [location object]: #location-object
 558
 559 [blacklisted]: options.md#blacklist
 560 [special options]: options.md#special-options
 561 [config file]: config-file.md
 562 [bootstrap.js]: config-file.md#bootstrapjs
 563 [autofocus prevention]: options.md#prevent-autofocus
 564 [`activatable_element_keys`]: options.md#activatable_element_keys
 565 [`adjustable_element_keys`]: options.md#adjustable_element_keys
 566
 567 [button]: button.md
 568 [special keys]: shortcuts.md#special-keys
 569 [styling]: styling.md
 570
 571 [defaults.coffee]: ../extension/lib/defaults.coffee
 572 [parse-prefs.coffee]: ../extension/lib/parse-prefs.coffee
 573 [modes.coffee]: ../extension/lib/modes.coffee
 574 [commands.coffee]: ../extension/lib/commands.coffee
 575 [vim.coffee]: ../extension/lib/vim.coffee
 576
 577 [`Window`]: https://developer.mozilla.org/en-US/docs/Web/API/Window
 578 [`Browser`]: https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XUL/browser
 579 [`Notification`]: https://developer.mozilla.org/en-US/docs/Web/API/Notification
 580 [`window.location`]: https://developer.mozilla.org/en-US/docs/Web/API/Location
 581 [`URL`]: https://developer.mozilla.org/en-US/docs/Web/API/URL
 582 [TabSelect]: https://developer.mozilla.org/en-US/docs/Web/Events/TabSelect
 583 [web console]: https://developer.mozilla.org/en-US/docs/Tools/Web_Console
 584 [about:config]: http://kb.mozillazine.org/About:config