OpacitySliderViewModel | API Reference | ArcGIS Maps SDK for JavaScript 4.31

Provides the logic for the OpacitySlider widget.

See also

OpacitySlider

Constructors

OpacitySliderViewModel Constructor new OpacitySliderViewModel(properties)

Parameter

properties Object

optional

See the properties for a list of all the properties that may be passed into the constructor.

Property Overview

Any properties can be set, retrieved or listened to. See the Watch for changes topic.

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Type	Summary	Class
String	The name of the class.	Accessor
Number	When set, the user is restricted from moving slider thumbs to positions higher than this value.	SliderViewModel
Number	When set, the user is restricted from moving slider thumbs to positions less than this value.	SliderViewModel
LabelFormatter	A function used to format user inputs.	SliderViewModel
InputParser	Function used to parse slider inputs formatted by the inputFormatFunction.	SliderViewModel
LabelFormatter	A function used to format labels.	SliderViewModel
String []	An array of strings associated with values generated using an internal label formatter or the values returned from labelFormatFunction.	SmartMappingSliderViewModel
Number	Defines how slider values should be rounded.	SliderViewModel
String	The state of the view model.	SmartMappingSliderViewModel
OpacityStop []	The opacity stops from the OpacityVariable to link to the slider.	OpacitySliderViewModel
Boolean	When `false`, the user can freely move any slider thumb to any position along the track.	SliderViewModel
Number []	The data values associated with the thumb locations of the slider.	SmartMappingSliderViewModel
Object	Zooms the slider track to the bounds provided in this property.	SmartMappingSliderViewModel
Boolean	Enables zooming on the slider.	SmartMappingSliderViewModel

Property Details

declaredClass Inherited Property declaredClass Stringreadonly Inherited from Accessor

The name of the class. The declared class name is formatted as esri.folder.className.

effectiveMax Inherited Property effectiveMax Number Inherited from SliderViewModel Since: ArcGIS Maps SDK for JavaScript 4.23 SliderViewModel since 4.12, effectiveMax added at 4.23.

When set, the user is restricted from moving slider thumbs to positions higher than this value. This value should be less than the slider max. The effectiveMax and effectiveMin allow you to represent ranges of values in a dataset that cannot be filtered or selected with the slider. This can be useful when using the slider to represent datasets with outliers, or scale ranges not suitable for a layer.

Example

// slider.viewModel.max = 100
slider.viewModel.effectiveMax = 60;
// now the user cannot slide thumbs above
// 60 even though the slider track displays
// values up to 100.

effectiveMin Inherited Property effectiveMin Number Inherited from SliderViewModel Since: ArcGIS Maps SDK for JavaScript 4.23 SliderViewModel since 4.12, effectiveMin added at 4.23.

When set, the user is restricted from moving slider thumbs to positions less than this value. This value should be greater than the slider min. The effectiveMin and effectiveMax allow you to represent ranges of values in a dataset that cannot be filtered or selected with the slider. This can be useful when using the slider to represent datasets with outliers, or scale ranges not suitable for a layer.

Example

// slider.viewModel.min = 0
slider.viewModel.effectiveMin = 4;
// now the user cannot slide thumbs below
// 4 even though the slider track displays
// values down to 0.

inputFormatFunction Inherited Property inputFormatFunction LabelFormatter Inherited from SliderViewModel

A function used to format user inputs. As opposed to labelFormatFunction, which formats thumb labels, the inputFormatFunction formats thumb values in the input element when the user begins to edit them.

The image below demonstrates how slider input values resemble corresponding slider values by default and won't match the formatting set in labelFormatFunction.

Slider without input formatter

If you want to format slider input values so they match thumb labels, you can pass the same function set in labelFormatFunction to inputFormatFunction for consistent formatting.

Slider with input formatter

However, if an inputFormatFunction is specified, you must also write a corresponding inputParseFunction to parse user inputs to understandable slider values. In most cases, if you specify an inputFormatFunction, you should set the labelFormatFunction to the same value for consistency between labels and inputs.

This property overrides the default input formatter, which formats by calling toString() on the input value.

See also

inputParseFunction

Example

// Formats the slider input to abbreviated numbers with units
// e.g. a thumb at position 1500 will render with an input label of 1.5k
slider.inputFormatFunction = function(value, type){
  if(value >= 1000000){
    return (value / 1000000).toPrecision(3) + "m"
  }
  if(value >= 100000){
    return (value / 1000).toPrecision(3) + "k"
  }
  if(value >= 1000){
    return (value / 1000).toPrecision(2) + "k"
  }
  return value.toFixed(0);
}

inputParseFunction Inherited Property inputParseFunction InputParser Inherited from SliderViewModel

Function used to parse slider inputs formatted by the inputFormatFunction. This property must be set if an inputFormatFunction is set. Otherwise the slider values will likely not update to their expected positions.

Overrides the default input parses, which is a parsed floating point number.

See also

inputFormatFunction

Example

// Parses the slider input (a string value) to a number value understandable to the slider
// This assumes the slider was already configured with an inputFormatFunction
// For example, if the input is 1.5k this function will parse
// it to a value of 1500
slider.inputParseFunction = function(value, type, index){
  let charLength = value.length;
  let valuePrefix = parseFloat(value.substring(0,charLength-1));
  let finalChar = value.substring(charLength-1);

  if(parseFloat(finalChar) >= 0){
    return parseFloat(value);
  }
  if(finalChar === "k"){
    return valuePrefix * 1000;
  }
  if(finalChar === "m"){
    return valuePrefix * 1000000;
  }
  return value;
}

labelFormatFunction Inherited Property labelFormatFunction LabelFormatter Inherited from SliderViewModel

A function used to format labels. Overrides the default label formatter.

By default labels are formatted in the following way:

When the data range is less than 10 ((max - min) < 10), labels are rounded based on the value set in the precision property.
When the data range is larger than 10, labels display with a precision of no more than two decimal places, though actual slider thumb values will maintain the precision specified in precision.

Use this property to override the behavior defined above.

Example

// For thumb values, rounds each label to whole numbers.
// Note the actual value of the thumb continues to be stored
// based on the indicated data `precision` despite this formatting
sliderViewModel.labelFormatFunction = function(value, type) {
  return (type === "value") ? value.toFixed(0) : value;
}

labels Inherited Property labels String[]readonly Inherited from SmartMappingSliderViewModel

An array of strings associated with values generated using an internal label formatter or the values returned from labelFormatFunction.

precision Inherited Property precision Number Inherited from SliderViewModel

Defines how slider values should be rounded. This number indicates the number of decimal places slider values should round to when they have been moved.

This value also indicates the precision of thumb labels when the data range (max - min) is less than 10.

When the data range is larger than 10, labels display with a precision of no more than two decimal places, though actual slider thumb values will maintain the precision specified in this property.

For example, given the default precision of 4, and the following slider configuration, The label of the thumb will display two decimal places, but the precision of the actual thumb value will not be lost even when the user slides or moves the thumb.

const slider = new SliderVM({
  min: 20,
  max: 100,  // data range of 80
  values: [50.4331],
  // thumb label will display 50.43
  // thumb value will maintain precision, so
  // value will remain at 50.4331
});

If the user manually enters a value that has a higher precision than what's indicated by this property, the precision of that thumb value will be maintained until the thumb is moved by the user. At that point, the value will be rounded according to the indicated precision.

If thumb labels aren't visible, they must be enabled with labelInputsEnabled.

Keep in mind this property rounds thumb values and shouldn't be used exclusively for formatting purposes. To format thumb labels, use the labelFormatFunction property.

Default Value:4

Example

sliderViewModel.precision = 7;

state Inherited Property state Stringreadonly Inherited from SmartMappingSliderViewModel

The state of the view model.

Possible Values:"ready" |"disabled"

stops Property stops OpacityStop[]

The opacity stops from the OpacityVariable to link to the slider. The opacity values in these stops will be used to render the gradient on the slider. They should match the opacity rendered in the associated layer's opacity visual variable.

Example

opacityVariableCreator.createContinuousRenderer({
  layer: featureLayer,
  field: "fieldName",
  basemap: "gray-vector"
}).then(function(opacityResponse){
  const slider = new OpacitySlider({
    viewModel: new OpacitySliderVM({
      stops: opacityResponse.visualVariable.stops
    }),
    container: "sliderDiv"
  });
});

thumbsConstrained Inherited Property thumbsConstrained Boolean Inherited from SliderViewModel

When false, the user can freely move any slider thumb to any position along the track. By default, a thumb's position is constrained to the positions of neighboring thumbs so you cannot move one thumb past another. Set this property to false to disable this constraining behavior.

Default Value:true

Example

// allows the user to freely move slider
// thumbs to any position along the track
slider.viewModel.thumbsConstrained = false;

values Inherited Property values Number[]readonly Inherited from SmartMappingSliderViewModel

The data values associated with the thumb locations of the slider. These are computed from the stops. Actual thumb locations depend on the number of stops provided.

See also

setValue

zoomOptions Inherited Property zoomOptions Object Inherited from SmartMappingSliderViewModel

Zooms the slider track to the bounds provided in this property. When min and/or max zoom values are provided, the absolute min and max slider values are preserved and rendered at their typical positions on the slider. However, the slider track itself is zoomed so that thumbs cannot be moved above or below the provided min and max zoomed values.

When a slider is in a zoomed state, the zoomed ends of the track will appear jagged. In the image below, notice how the top thumb cannot be moved past the zoom max of 31 even though the slider max is 200.

slider-zoom

To exit a zoomed state, the user can click the jagged line or the developer can set the zoomOptions to null. It is up to the developer to provide a UI option for end users to enable zooming on the slider.

Setting the zoomOptions is useful when the slider is tied to heavily skewed datasets where the histogram renders only one or two bars because of outliers.

slider-not-zoomed

You can remove the influence of outliers by zooming the slider and regenerating a histogram based on the zoomed min and max. This will provide a better view of the data and make the slider more useful to the end user.

Properties: min Number

optional
The lower bound of the zoom.

max Number

optional
The upper bound of the zoom.

Examples

// zooms the slider to so thumbs can only be moved
// to positions between the values of 10 and 25 while
// maintaining the slider's absolute minimum and
// maximum values
slider.viewModel.zoomOptions = {
  min: 10,
  max: 25
};

// disables zooming on the slider
slider.viewModel.zoomOptions = null;

// zooms the slider to so thumbs can only be moved
// to positions above the value of 10, while maintaining
// the slider's absolute minimum value
slider.viewModel.zoomOptions = {
  min: 10
};

// zooms the slider to so thumbs can only be moved
// to positions below the value of 25, while maintaining
// the slider's absolute maximum value
slider.viewModel.zoomOptions = {
  max: 25
};

// zooms the slider to the handle positions
// with some padding
document.getElementById("zoomInButton").onclick = function() {
  const lowerThumb = slider.values[0];
  const upperThumb = slider.values[1];

  const range = upperThumb - lowerThumb;
  const padding = range * 0.3;

  const zoomMin = (lowerThumb - padding) > slider.min ? (lowerThumb - padding) : slider.min;
  const zoomMax = (upperThumb + padding) < slider.max ? (upperThumb + padding) : slider.max;

  slider.viewModel.set({ zoomOptions: { min: zoomMin, max: zoomMax } });
};

zoomingEnabled Inherited Property zoomingEnabled Boolean Inherited from SmartMappingSliderViewModel

Enables zooming on the slider. See zoomOptions for more information on zooming along the slider track.

See also

zoomOptions

Example

// disables zooming on the slider
slider.viewModel.zoomingEnabled = false;

Method Overview

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Return Type	Summary	Class
	Adds one or more handles which are to be tied to the lifecycle of the object.	Accessor
String	The default input format function available for use as a fallback in custom formatting implementations.	SliderViewModel
Number	The default input parsing function available for use as a fallback in custom parsing implementations.	SliderViewModel
String	The default label format function, available for use as a fallback in custom formatting implementations.	SliderViewModel
Boolean	Emits an event on the instance.	SliderViewModel
Bounds	Returns the effective bounds of the slider.	SliderViewModel
Object	Returns the min and max bounds for a 'value' at the provided index.	SliderViewModel
String	Returns the formatted label for a provided value.	SliderViewModel
StopInfo []	Generates the opacity ramp gradient rendered on the slider.	OpacitySliderViewModel
	Gets the max value of the slider.	SmartMappingSliderViewModel
	Gets the min value of the slider.	SmartMappingSliderViewModel
Boolean	Indicates whether there is an event listener on the instance that matches the provided event name.	SliderViewModel
Boolean	Returns true if a named group of handles exist.	Accessor
Object	Registers an event handler on the instance.	SliderViewModel
	Removes a group of handles owned by the object.	Accessor
	Updates a thumb value based on the provided index.	SliderViewModel
String	Rounds the given value to the number of decimal places specified in the precision property set on the view model.	SliderViewModel

Method Details

addHandles Inherited Method addHandles(handleOrHandles, groupKey) Inherited from Accessor Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, addHandles added at 4.25.

Adds one or more handles which are to be tied to the lifecycle of the object. The handles will be removed when the object is destroyed.

// Manually manage handles
const handle = reactiveUtils.when(
  () => !view.updating,
  () => {
    wkidSelect.disabled = false;
  },
  { once: true }
);

this.addHandles(handle);

// Destroy the object
this.destroy();

Parameters

handleOrHandles WatchHandle|WatchHandle []

Handles marked for removal once the object is destroyed.

groupKey *

optional

Key identifying the group to which the handles should be added. All the handles in the group can later be removed with Accessor.removeHandles(). If no key is provided the handles are added to a default group.

defaultInputFormatFunction Inherited Method defaultInputFormatFunction(value){String} Inherited from SliderViewModel

The default input format function available for use as a fallback in custom formatting implementations.

Parameter

value Number

The input value to format.

Returns

Type	Description
String	The formatted input value.

defaultInputParseFunction Inherited Method defaultInputParseFunction(value){Number} Inherited from SliderViewModel

The default input parsing function available for use as a fallback in custom parsing implementations.

Parameter

value String

The thumb value to parse.

Returns

Type	Description
Number	The parsed thumb value.

defaultLabelFormatFunction Inherited Method defaultLabelFormatFunction(value){String} Inherited from SliderViewModel

The default label format function, available for use as a fallback in custom formatting implementations.

Parameter

value Number

The thumb value to format.

Returns

Type	Description
String	The formatted thumb value.

emit Inherited Method emit(type, event){Boolean} Inherited from SliderViewModel

Emits an event on the instance. This method should only be used when creating subclasses of this class.

Parameters

type String

The name of the event.

event Object

optional

The event payload.

Returns

Type	Description
Boolean	`true` if a listener was notified

getBounds Inherited Method getBounds(){Bounds} Inherited from SliderViewModel Since: ArcGIS Maps SDK for JavaScript 4.23 SliderViewModel since 4.12, getBounds added at 4.23.

Returns the effective bounds of the slider. If effectiveMin and effectiveMax are set on the slider, then those values will be returned. If not, then the min and max are returned.

Returns

Type	Description
Bounds	The effective bounds of the slider.

getBoundsForValueAtIndex Inherited Method getBoundsForValueAtIndex(index){Object} Inherited from SliderViewModel

Returns the min and max bounds for a 'value' at the provided index. Also used internally to provide accessibility information via HTMLElement properties

Parameter

index Number

The index of the associated value.

Returns

Type	Description
Object	Returns a simple object with bound information.

getLabelForValue Inherited Method getLabelForValue(value, type, index){String} Inherited from SliderViewModel

Returns the formatted label for a provided value.

Parameters

value Number

The value from which to retrieve a formatted label.

type String

optional

The label type.

Possible Values:"min"|"max"|"tick"|"values"

index Number

optional

The index of the label.

Returns

Type	Description
String	Returns the formatted label.

getStopInfo Method getStopInfo(){StopInfo[]}

Generates the opacity ramp gradient rendered on the slider.

Returns

Type	Description
StopInfo []

getUnzoomedMax Inherited Method getUnzoomedMax() Inherited from SmartMappingSliderViewModel

Gets the max value of the slider. This is useful for when the user wants to change the slider max when it is not visible in the zoomed state.

See also

zoomOptions

getUnzoomedMin Inherited Method getUnzoomedMin() Inherited from SmartMappingSliderViewModel

Gets the min value of the slider. This is useful for when the user wants to change the slider min when it is not visible in the zoomed state.

See also

zoomOptions

hasEventListener Inherited Method hasEventListener(type){Boolean} Inherited from SliderViewModel

Indicates whether there is an event listener on the instance that matches the provided event name.

Parameter

type String

The name of the event.

Returns

Type	Description
Boolean	Returns true if the class supports the input event.

hasHandles Inherited Method hasHandles(groupKey){Boolean} Inherited from Accessor Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, hasHandles added at 4.25.

Returns true if a named group of handles exist.

Parameter

groupKey *

optional

A group key.

Returns

Type	Description
Boolean	Returns `true` if a named group of handles exist.

Example

// Remove a named group of handles if they exist.
if (obj.hasHandles("watch-view-updates")) {
  obj.removeHandles("watch-view-updates");
}

on Inherited Method on(type, listener){Object} Inherited from SliderViewModel

Registers an event handler on the instance. Call this method to hook an event with a listener.

Parameters

type String|String []

An event or an array of events to listen for.

listener Function

The function to call when the event fires.

Returns

Type Description

Object

Returns an event handler with a remove() method that should be called to stop listening for the event(s).

Property	Type	Description
remove	Function	When called, removes the listener from the event.

Example

view.on("click", function(event){
  // event is the event handle returned after the event fires.
  console.log(event.mapPoint);
});

removeHandles Inherited Method removeHandles(groupKey) Inherited from Accessor Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, removeHandles added at 4.25.

Removes a group of handles owned by the object.

Parameter

groupKey *

optional

A group key or an array or collection of group keys to remove.

Example

obj.removeHandles(); // removes handles from default group

obj.removeHandles("handle-group");
obj.removeHandles("other-handle-group");

setValue Inherited Method setValue(index, value) Inherited from SliderViewModel

Updates a thumb value based on the provided index. The provided value must differ from the previous value. The provided value must also be between the min and max.

Parameters

index Number

The index of the thumb value in the associated values array.

value Number

The new value to replace with the old value.

toPrecision Inherited Method toPrecision(value){String} Inherited from SliderViewModel Since: ArcGIS Maps SDK for JavaScript 4.14 SliderViewModel since 4.12, toPrecision added at 4.14.

Rounds the given value to the number of decimal places specified in the precision property set on the view model.

Parameter

value Number

The thumb value to format.

Returns

Type	Description
String	The input value rounded to the number of places specified in precision.

See also

precision

Type Definitions

StopInfo Type Definition StopInfo

The return object of the getStopInfo() method.

Properties: color Color

The color of the stop.

offset Number

The offset of the stop.