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Roll20 makes a number of functions available that are not part of core JavaScript or some other library.

Global variables

Variable	Description
`_`	This is the namespace object for the Underscore.js library.
`state`	Properties of the state object will persist between game sessions.

`_` (Underscore)

This is the namespace object for the Underscore.js library. Underscore has many functions for collection manipulation.

`state`

Properties of the state object will persist between game sessions. The same state object is also shared between all API scripts in a campaign, so it is strongly recommended that when writing values to state, you minimize your footprint as much as possible in order to avoid name collisions. Note: state gets serialized with JSON, so you cannot store functions or objects with cyclical references.

Global functions

Return type	Function	Description
Roll20 object	`Campaign`	Gets the singleton Campaign Roll20 object.
Roll20 object	`createObj`	Creates a new Roll20 object.
Array of Roll20 objects	`filterObjs`	Gets all Roll20 objects which pass a predicate test.
Array of Roll20 objects	`findObjs`	Gets all Roll20 objects with properties that match a given set of attributes.
Array of Roll20 objects	`getAllObjs`	Gets all Roll20 objects in the campaign.
varies	`getAttrByName`	Gets the current or max value of an attribute Roll20 object.
Roll20 object	`getObj`	Gets a specific Roll20 object.
	`log`	Logs a message to the API console.
	`on`	Registers an event handler.
Boolean	`playerIsGM`	Checks whether a player currently has GM privileges.
	`playJukeboxPlaylist`	Start playing a jukebox playlist.
Number	`randomInteger`	Generates a random integer value.
	`sendChat`	Sends a chat message.
	`sendPing`	Sends a ping similar to holding the left mouse button.
	`spawnFx`	Spawns a particle emitter.
	`spawnFxBetweenPoints`	Spawns a particle emitter that moves from one point to another.
	`spawnFxWithDefinition`	Spawns a particle emitter that is not represented by an FX Roll20 object.
	`stopJukeboxPlaylist`	Stops all currently playing jukebox playlits.
	`toBack`	Moves a graphic Roll20 object below all of the other graphics on the same tabletop layer.
	`toFront`	Moves a graphic Roll20 object above all of the other graphics on the same tabletop layer.

`Campaign`

Parameters

No parameters

Returns

The singleton campaign Roll20 object.

Examples

var currentPageID = Campaign().get('playerpageid'),
    currentPage = getObj('page', currentPageID);

`createObj`

Parameters

type: (String) The type of Roll20 object to create. Only 'graphic', 'text', 'path', 'character', 'ability', 'attribute', 'handout', 'rollabletable', 'tableitem', and 'macro' may be created.
attributes: (Object) The initial values to use for the Roll20 object's properties.

Returns

The Roll20 object that was created.

Examples

When creating a Roll20 object that has a parent object (such as creating an attribute Roll20 object, which is a child of a character Roll20 object), you must supply the id of the parent in attributes.

on('add:character', function(obj) {
    createObj('attribute', {
        name: 'Strength',
        current: 0,
        max: 30,
        characterid: obj.id
    });
});

When creating a path Roll20 object, you must supply a value for the read-only property _path. This is an exception to the rule that prevents you from setting the value of read-only properties when creating Roll20 objects.

createObj('path', {
    left: 7000,
    top: 140,
    width: 140,
    height: 140,
    layer: 'objects',
    path: JSON.stringify([['M', 0, 0], ['L', 70, 0], ['L', 0, 70], ['L', 0, 0]])
});

When creating a handout Roll20 object, you cannot set the text or gmnotes at the time of creation.

var handout = createObj('handout', {
    name: 'A Letter Addressed to You',
    inplayerjournals: 'all',
    archived: false
});
handout.set({
    notes: 'Notes can only be set after the handout is created',
    gmnotes: 'GM Notes can only be set after the handout is created'
});

`filterObjs`

Parameters

callback: (Function) A predicate function to test all Roll20 objects against. The callback function receives a Roll20 object as a parameter, and should return either true (for Roll20 objects that will be included in the filterObjs return value) or false (for all other Roll20 objects).

Returns

An array of Roll20 objects which passed the predicate test.

Examples

var tokenName = getMyTokenName(),
    duplicateTokens = filterObjs(function(obj) {
        if (obj.get('type') !== 'graphic' || obj.get('subtype') !== 'token' || obj.get('name') === tokenName) return false;
        return obj.get('name').indexOf(tokenName) === 0 && /\d+$/.text(obj.get('name'));
    });

`findObjs`

Parameters

attributes: (Object) A collection of key:value pairs to match with Roll20 objects in the campaign.
options: (Object, optional) If options.caseInsensitive is true, string comparisons between Roll20 objects and attributes will be case-insensitive.

Returns

An array of Roll20 objects with properties that match attributes.

Examples

var npcs = findObjs({ type: 'character', controlledby: '' });

`getAllObjs`

Parameters

No parameters

Returns

An array of all Roll20 objects in the campaign.

Examples

var everything = getAllObjs();

`getAttrByName`

Parameters

character_id: (String) The id of the character Roll20 object that is the parent of the attribute Roll20 object you want the value of.
attribute_name: (String) The name of the attribute Roll20 object you want the value of.
value_type: (String, optional) Either "current" or "max" (defaults to "current" if omitted).

Returns

The current or max property of the appropriate attribute. If the desired property is not set, the default value specified by the character sheet (if there is a default) will be used instead.

Examples

var character = getMyCharacter(),
    strength = getAttrByName(character.id, 'strength'),
    strength_max = getAttrByName(character.id, 'strength', 'max');

`getObj`

Parameters

type: (String) The type of Roll20 object to get.
id: (String) The unique id for the Roll20 object to get.

Returns

The specified Roll20 object.

Examples

on('chat:message', function(msg) {
    var sendingPlayer = getObj('player', msg.playerid);
});

`log`

Parameters

message: (varies) The message to post to the API console. The message parameter will be transformed into a String with JSON.stringify.

Returns

(Void)

Examples

on('chat:message', function(msg) {
    log('Message received from:');
    log(getObj('player', msg.playerid));
});

"Message received from:"

{"_d20userid":"123456","_displayname":"John Doe","speakingas":"","_online":true,"color":"#885b68","_macrobar":"-J16Z-dRU5tleKiKOg0X|-K3F_4q_b1p-Vdiwgn1t","showmacrobar":true,"_id":"-J16Z-dRU5tleKiKOc0X","_type":"player","_lastpage":""}

`on`

Parameters

event

(String) There are five types of event:

ready
change
add
destroy
chat

With the exception of ready, all event types must also be paired with an object type. For chat, this is always message. For everything else, this is the type property of a Roll20 object. In addition to the object type, change events can also optionally specify a property of the specified Roll20 object to watch.

The 2-3 parts of the event (type, object, and optionally property) are separated by colons. So, valid event strings include but are not limited to "ready", "chat:message", "change:graphic", "change:campaign:playerpageid", "add:character", and "destroy:handout".

callback

(Function) The function that will be called when the specified event fires. The parameters passed depend on the event type:

ready events have no callback parameters.
change events have an obj parameter, which is a reference to the Roll20 object as it exists after the change, and a prev parameter, which is a plain old JavaScript object with properties matching the Roll20 object prior to the change event.
add events have an obj parameter, which is a reference to the new Roll20 object.
destroy events have an obj parameter, which is a reference to the no-longer existing Roll20 object.
chat events have a msg parameter, which contains the details of the message that was sent to the chat.

Returns

(Void)

Examples

Events are fired in the order they were registered, and from most to least specific. In this example, a change to a graphic Roll20 object's left property will result in function3 getting called, followed by function1 and then function2.

on('change:graphic', function1);
on('change:graphic', function2);
on('change:graphic:left', function3);

add events will attempt to fire for Roll20 objects that are already in the campaign when a new session starts. In order to prevent this behavior, you can wait to register your add event until the ready event fires.

on('add:graphic', function(obj) {
    // When the session begins, this function will be called for every graphic in the campaign
    // This function will also be called whenever a new graphic Roll20 object is created
});

on('ready', function() {
    on('add:graphic', function(obj) {
        // This function will *only* be called when a new graphic Roll20 object is created, not for ones that already exist
    });
});

The pre parameter for change events is not a Roll20 object, it is a plain old JavaScript object. As such, you cannot use the get or set functions, and you cannot omit the leading underscores on read-only properties.

on('change:graphic', function(obj, prev) {
    var id1 = obj.id,         // all three are equivalent
        id2 = obj.get('id'),
        id3 = obj.get('_id'),

        id4 = prev.id,        // undefined
        id5 = prev.get('id'), // undefined is not a function
        id6 = prev._id;       // correct

    // both are equivalent
    obj.set('left', 70);
    obj.set({
        left: 70
    });

    prev.set('left', 70); // undefined is not a function
    prev.set({            // undefined is not a function
        left: 70
    });
    prev.left = 70;       // correct, although it won't change anything on the tabletop
});

For the async fields of character and handout Roll20 objects (notes, gmnotes, and bio), the prev parameter will not hold the data you need. (It will have a numeric identifier used by the system instead.) If you need to access the previous value of one of these fields, you will have to keep track of it yourself:

on('ready', function() {
    if (!state.example) state.example = { bioCache: {} };
});

on('change:character:bio', function(obj, prev) {
    obj.get('bio', function(text) {
        state.example.bioCache[obj.id] = text;

        // do stuff...

        if (shouldRevertBio()) {
            obj.set('bio', state.example.bioCache[obj.id]);
        }
    });
});

`playerIsGM`

Parameters

player_id: (String) The id of the player Roll20 object to check.

Returns

true if the player currently has GM permissions, or false otherwise.

Examples

This function is especially useful for limiting API commands to GM use.

on('chat:message', function(msg) {
    if (msg.type !== 'api') return;

    if (msg.content.indexOf('!playercommand') === 0) {
        // ...
    } else if (msg.content.indexOf('!gmcommand') === 0) {
        if (!playerIsGM(msg.playerid)) return;
        // ...
    }
});

`playJukeboxPlaylist`

Parameters

playlist_id: (String) The id of the playlist to start playing.

Returns

(Void)

Examples

var playlists = JSON.parse(Campaign().get('jukeboxfolder')),
    myPlaylist = _.find(playlists, (folder) => _.isObject(folder) && folder.n === myPlaylistName);
playJukeboxPlaylist(myPlaylist.id);

`randomInteger`

Parameters

max: (Number) The maximum number to return, inclusive.

Returns

A random integer between 1 (inclusive) and max (inclusive). This function has better distribution than Math.random(), and is recommended over it. This function doesn't make use of the Quantum Roll feature used by the dice engine, but it does use the same pseudorandom algorithm that the dice engine will fall back on if Quantum Roll is unavailable.

Examples

Because this function returns an integer from 1 to max, it is ideal for quickly generating a dice roll outcome if you don't need the full strength of Roll20's dice engine.

var d20Result = randomInteger(20); // roughly equivalent to rolling a 20-sided die

`sendChat` [Asynchronous]

Parameters

speakingAs: (String) The name to attach to the message being sent. If speakingAs is in the format player|player_id or character|character_id, the message will be sent as that player or character. Otherwise, the message will use the given name as though a GM had used the /as command.
message: (String) The message to send to the chat.
callback: (Function, optional) If callback is specified, the result of the chat message will be passed to it instead of appearing in the chat. The parameter of the callback method is an array of message objects.
options: (Object, optional) If options.noarchive is true, the message will not be added to the chat archive. If options.use3d is true, dice rolls in the message will use the 3D dice feature. Options are not applicable if callback is specified.

Returns

(Void)

Examples

sendChat('Example', 'This is a simple example.');

You can easily write code to send a message as the same player or character that triggered a chat:message event.

on('chat:message', function(msg) {
    var character = findObjs({ type: 'character', name: msg.who })[0],
        player = getObj('player', msg.playerid),
        message = ' said something';

    if (character) sendChat('character|'+character.id, character.get('name')+message);
    else sendChat('player|'+player.id, player.get('displayname')+message);
});

The callback parameter is useful if you need to leverage Roll20's dice engine. There is no particular need for a speakingAs value when using the callback, since the message won't appear in the chat anyway.

sendChat('', '/r 2d20k1+'+strengthMod, function(ops) {
    var msg = ops[0];
    // ...
});

options.noarchive is primarily designed for sending players menus made from API Command buttons without clogging their chat history.

sendChat('System', '[Clear changes](!clear)\n[Add tile](!add)\n[View sample](!view)\n[Save layout](!save)', null, { noarchive: true });

`sendPing`

Parameters

left: (Number) The x-coordinate to place the ping at.
top: (Number) The y-coordinate to place the ping at.
page_id: (String) The id of the page Roll20 object to place the ping on.
player_id: (String, optional) The ping will use the specified player's color. If player_id is omitted, the ping will be yellow.
moveAll: (Boolean, optional) If moveAll is true, all of the players on the appropriate page will have their views centered on the ping.

Returns

(Void)

Examples

on('chat:message', function(msg) {
    var obj;
    if (msg.type === 'api' && msg.content.indexOf('!ping') === 0) {
        if (!msg.selected) return;
        obj = getObj(msg.selected[0]._type, msg.selected[0]._id);
        sendPing(obj.get('left'), obj.get('top'), obj.get('pageid'), msg.playerid, true); // center everyone on the selected token
    }
});

`spawnFx`

Parameters

left: (Number) The x-coordinate to place the particle emitter.
top: (Number) The y-coordinate to place the particle emitter.
type: (String) The type of particle emitter to place. For built-in effects, this should be "type-color", where type is one of bomb, bubbling, burn, burst, explode, glow, missile, or nova and color is one of acid, blood, charm, death, fire, frost, holy, magic, slime, smoke, or water. For custom effects, this should be the id of the FX Roll20 object.; Note: beam, breath, and splatter types cannot be used with spawnFx. See spawnFxBetweenPoints instead.
page_id: (String, optional) The id of the page Roll20 object to place the particle emitter on. If omitted, Campaign().get('playerpageid') will be used instead.

Returns

(Void)

Examples

spawnFx(1400, 1400, 'bubbling-acid');

`spawnFxBetweenPoints`

Parameters

start: (Object) The starting point for the particle emitter. The point should be in the format { x: number, y: number }.
end: (Object) The ending point for the particle emitter. The point should be in the format { x: number, y: number }.
type: (String) The type of particle emitter to place. For built-in effects, this should be "type-color", where type is one of beam, bomb, breath, bubbling, burn, burst, explode, glow, missile, nova, or splatter and color is one of acid, blood, charm, death, fire, frost, holy, magic, slime, smoke, or water. For custom effects, this should be the id of the FX Roll20 object.
page_id: (String, optional) The id of the page Roll20 object to place the particle emitter on. If omitted, Campaign().get('playerpageid') will be used instead.

Returns

(Void)

Examples

spawnFxBetweenPoints({ x: 1400, y: 1400 }, { x: 2100, y: 2100 }, 'beam-acid');

`spawnFxWithDefinition`

Parameters

left: (Number) The x-coordinate to place the particle emitter.
top: (Number) The y-coordinate to place the particle emitter.
definition: (Object) The characteristics of the particle emitter to place. See Custom FX for a list of possible properties and the properties of the default particle emitter types and colors. See FX Library for some custom effects Roll20 users have come up with.
page_id: (String, optional) The id of the page Roll20 object to place the particle emitter on. If omitted, Campaign().get('playerpageid') will be used instead.

Returns

(Void)

Examples

// these two are equivalent
spawnFx(1400, 1400, 'bubbling-acid');
spawnFxWithDefinition(1400, 1400, {
    maxParticles: 200,
    size: 15,
    sizeRandom: 3,
    lifeSpan: 20,
    lifeSpanRandom: 5,
    speed: 7,
    speedRandom: 2,
    gravity: { x: 0.01, y: 0.65 },
    angle: 270,
    angleRandom: 35,
    emissionRate: 1,
    startColour:       [0, 35, 10, 1],
    startColourRandom: [0, 10, 10, 0.25],
    endColour:         [0, 75, 30, 0],
    endColourRandom:   [0, 20, 20, 0]
});

`stopJukeboxPlaylist`

Parameters

No parameters

Returns

(Void)

Examples

stopJukeboxPlaylist();

`toBack`

Parameters

obj: (Roll20 object) The Roll20 object to send to the back of its layer.

Returns

(Void)

Examples

on('chat:message', function(msg) {
    if (msg.type === 'api' && msg.content === '!toback' && msg.selected) {
        _.each(msg.selected, (s) => {
            toBack(getObj(s._type, s._id));
        });
    }
});

`toFront`

Parameters

obj: (Roll20 object) The Roll20 object to bring to the front of its layer.

Returns

(Void)

Examples

on('ready', function() {
    on('add:graphic', function(obj) {
        toFront(obj);
    });
});

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Contents

Global variables

_ (Underscore)

state

Global functions

Campaign

Parameters

Returns

Examples

createObj

Parameters

Returns

Examples

filterObjs

Parameters

Returns

Examples

findObjs

Parameters

Returns

Examples

getAllObjs

Parameters

Returns

Examples

getAttrByName

Parameters

Returns

Examples

getObj

Parameters

Returns

Examples

log

Parameters

Returns

Examples

on

Parameters

Returns

Examples

playerIsGM

Parameters

Returns

Examples

playJukeboxPlaylist

Parameters

Returns

Examples

randomInteger

Parameters

Returns

Examples

sendChat [Asynchronous]

Parameters

Returns

Examples

sendPing

Parameters

Returns

Examples

spawnFx

Parameters

Returns

Examples

spawnFxBetweenPoints

Parameters

Returns

Examples

spawnFxWithDefinition

Parameters

Returns

Examples

stopJukeboxPlaylist

`_` (Underscore)

`state`

`Campaign`

`createObj`

`filterObjs`

`findObjs`

`getAllObjs`

`getAttrByName`

`getObj`

`log`

`on`

`playerIsGM`

`playJukeboxPlaylist`

`randomInteger`

`sendChat` [Asynchronous]

`sendPing`

`spawnFx`

`spawnFxBetweenPoints`

`spawnFxWithDefinition`

`stopJukeboxPlaylist`

`toBack`

`toFront`