Add Slider/RangeSlider tooltip.format and tooltip.style.

CHANGELOG.md

@@ -6,6 +6,9 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 
 ## Added
 - [#2695](https://github.com/plotly/dash/pull/2695) Adds  `triggered_id` to `dash_clientside.callback_context`.  Fixes [#2692](https://github.com/plotly/dash/issues/2692)
+- [#2723](https://github.com/plotly/dash/pull/2723) Improve dcc Slider/RangeSlider tooltips. Fixes [#1846](https://github.com/plotly/dash/issues/1846)
+  - Add `tooltip.format` a string for the format template, {value} will be formatted with the actual value.
+  - Add `tooltip.style` a style object to give to the div of the tooltip.
 - [#2732](https://github.com/plotly/dash/pull/2732) Add special key `_dash_error` to `setProps`, allowing component developers to send error without throwing in render. Usage `props.setProps({_dash_error: new Error("custom error")})`
 
 ## Fixed

components/dash-core-components/src/components/RangeSlider.react.js

@@ -125,6 +125,31 @@ RangeSlider.propTypes = {
             'bottomLeft',
             'bottomRight',
         ]),
+        /**
+         * Template string to display the tooltip in.
+         * Must contain `{value}`, which will be replaced with either
+         * the default string representation of the value or the result of the
+         * transform function if there is one.
+         */
+        template: PropTypes.string,
+        /**
+         * Custom style for the tooltip.
+         */
+        style: PropTypes.object,
+        /**
+         * Reference to a function in the `window.dccFunctions` namespace.
+         * This can be added in a script in the asset folder.
+         *
+         * For example, in `assets/tooltip.js`:
+         * ```
+         * window.dccFunctions = window.dccFunctions || {};
+         * window.dccFunctions.multByTen = function(value) {
+         *     return value * 10;
+         * }
+         * ```
+         * Then in the component `tooltip={'transform': 'multByTen'
+         */
+        transform: PropTypes.string,
     }),
 
     /**

components/dash-core-components/src/components/Slider.react.js

@@ -2,6 +2,8 @@ import React, {Component, lazy, Suspense} from 'react';
 import PropTypes from 'prop-types';
 import slider from '../utils/LazyLoader/slider';
 
+import './css/sliders.css';
+
 const RealSlider = lazy(slider);
 
 /**
@@ -105,6 +107,31 @@ Slider.propTypes = {
             'bottomLeft',
             'bottomRight',
         ]),
+        /**
+         * Template string to display the tooltip in.
+         * Must contain `{value}`, which will be replaced with either
+         * the default string representation of the value or the result of the
+         * transform function if there is one.
+         */
+        template: PropTypes.string,
+        /**
+         * Custom style for the tooltip.
+         */
+        style: PropTypes.object,
+        /**
+         * Reference to a function in the `window.dccFunctions` namespace.
+         * This can be added in a scrip in the asset folder.
+         *
+         * For example, in `assets/tooltip.js`:
+         * ```
+         * window.dccFunctions = window.dccFunctions || {};
+         * window.dccFunctions.multByTen = function(value) {
+         *     return value * 10;
+         * }
+         * ```
+         * Then in the component `tooltip={'transform': 'multByTen'
+         */
+        transform: PropTypes.string,
     }),
 
     /**

components/dash-core-components/src/components/css/sliders.css

@@ -0,0 +1,5 @@
+/* Fix the default tooltip style height conflicting with the actual size of the tooltip. */
+.rc-slider-tooltip-content > .rc-slider-tooltip-inner {
+    height: unset;
+    min-height: 20px;
+}

components/dash-core-components/src/fragments/RangeSlider.react.js

@@ -1,5 +1,5 @@
 import React, {Component} from 'react';
-import {assoc, pick, isNil} from 'ramda';
+import {assoc, pick, isNil, pipe, omit} from 'ramda';
 import {Range, createSliderWithTooltip} from 'rc-slider';
 import computeSliderStyle from '../utils/computeSliderStyle';
 
@@ -11,6 +11,10 @@ import {
     setUndefined,
 } from '../utils/computeSliderMarkers';
 import {propTypes, defaultProps} from '../components/RangeSlider.react';
+import {
+    formatSliderTooltip,
+    transformSliderTooltip,
+} from '../utils/formatSliderTooltip';
 
 const sliderProps = [
     'min',
@@ -72,17 +76,33 @@ export default class RangeSlider extends Component {
         } = this.props;
         const value = this.state.value;
 
-        let tipProps;
-        if (tooltip && tooltip.always_visible) {
+        let tipProps, tipFormatter;
+        if (tooltip) {
             /**
              * clone `tooltip` but with renamed key `always_visible` -> `visible`
-             * the rc-tooltip API uses `visible`, but `always_visible is more semantic
+             * the rc-tooltip API uses `visible`, but `always_visible` is more semantic
              * assigns the new (renamed) key to the old key and deletes the old key
              */
-            tipProps = assoc('visible', tooltip.always_visible, tooltip);
-            delete tipProps.always_visible;
-        } else {
-            tipProps = tooltip;
+            tipProps = pipe(
+                assoc('visible', tooltip.always_visible),
+                omit(['always_visible', 'template', 'style', 'transform'])
+            )(tooltip);
+            if (tooltip.template || tooltip.style || tooltip.transform) {
+                tipFormatter = tipValue => {
+                    let t = tipValue;
+                    if (tooltip.transform) {
+                        t = transformSliderTooltip(tooltip.transform, tipValue);
+                    }
+                    return (
+                        <div style={tooltip.style}>
+                            {formatSliderTooltip(
+                                tooltip.template || '{value}',
+                                t
+                            )}
+                        </div>
+                    );
+                };
+            }
         }
 
         return (
@@ -116,6 +136,7 @@ export default class RangeSlider extends Component {
                         ...tipProps,
                         getTooltipContainer: node => node,
                     }}
+                    tipFormatter={tipFormatter}
                     style={{position: 'relative'}}
                     value={value ? value : calcValue(min, max, value)}
                     marks={sanitizeMarks({min, max, marks, step})}

components/dash-core-components/src/fragments/Slider.react.js

@@ -1,6 +1,6 @@
 import React, {Component} from 'react';
 import ReactSlider, {createSliderWithTooltip} from 'rc-slider';
-import {assoc, isNil, pick} from 'ramda';
+import {assoc, isNil, pick, pipe, omit} from 'ramda';
 import computeSliderStyle from '../utils/computeSliderStyle';
 
 import 'rc-slider/assets/index.css';
@@ -11,6 +11,10 @@ import {
     setUndefined,
 } from '../utils/computeSliderMarkers';
 import {propTypes, defaultProps} from '../components/Slider.react';
+import {
+    formatSliderTooltip,
+    transformSliderTooltip,
+} from '../utils/formatSliderTooltip';
 
 const sliderProps = [
     'min',
@@ -72,17 +76,33 @@ export default class Slider extends Component {
         } = this.props;
         const value = this.state.value;
 
-        let tipProps;
-        if (tooltip && tooltip.always_visible) {
+        let tipProps, tipFormatter;
+        if (tooltip) {
             /**
              * clone `tooltip` but with renamed key `always_visible` -> `visible`
              * the rc-tooltip API uses `visible`, but `always_visible` is more semantic
              * assigns the new (renamed) key to the old key and deletes the old key
              */
-            tipProps = assoc('visible', tooltip.always_visible, tooltip);
-            delete tipProps.always_visible;
-        } else {
-            tipProps = tooltip;
+            tipProps = pipe(
+                assoc('visible', tooltip.always_visible),
+                omit(['always_visible', 'template', 'style', 'transform'])
+            )(tooltip);
+            if (tooltip.template || tooltip.style || tooltip.transform) {
+                tipFormatter = tipValue => {
+                    let t = tipValue;
+                    if (tooltip.transform) {
+                        t = transformSliderTooltip(tooltip.transform, tipValue);
+                    }
+                    return (
+                        <div style={tooltip.style}>
+                            {formatSliderTooltip(
+                                tooltip.template || '{value}',
+                                t
+                            )}
+                        </div>
+                    );
+                };
+            }
         }
 
         return (
@@ -116,6 +136,7 @@ export default class Slider extends Component {
                         ...tipProps,
                         getTooltipContainer: node => node,
                     }}
+                    tipFormatter={tipFormatter}
                     style={{position: 'relative'}}
                     value={value}
                     marks={sanitizeMarks({min, max, marks, step})}

components/dash-core-components/src/utils/formatSliderTooltip.js

@@ -0,0 +1,19 @@
+import {replace, path, split, concat, pipe} from 'ramda';
+
+export const formatSliderTooltip = (template, value) => {
+    return replace('{value}', value, template);
+};
+
+export const transformSliderTooltip = (funcName, value) => {
+    const func = pipe(
+        split('.'),
+        s => concat(['dccFunctions'], s),
+        s => path(s, window)
+    )(funcName);
+    if (!func) {
+        throw new Error(
+            `Invalid func for slider tooltip transform: ${funcName}`
+        );
+    }
+    return func(value);
+};

components/dash-core-components/tests/integration/sliders/assets/transform.js

@@ -0,0 +1,4 @@
+window.dccFunctions = window.dccFunctions || {};
+window.dccFunctions.transformTooltip = function(value) {
+    return "Transformed " + value
+}

components/dash-core-components/tests/integration/sliders/test_sliders.py

@@ -559,3 +559,60 @@ def test_slsl015_range_slider_no_min_max(dash_dcc):
     )
 
     assert dash_dcc.get_logs() == []
+
+
+def test_sls016_sliders_format_tooltips(dash_dcc):
+    app = Dash(__name__)
+    app.layout = html.Div(
+        [
+            dcc.Slider(
+                value=34,
+                min=20,
+                max=100,
+                id="slider",
+                tooltip={
+                    "template": "Custom tooltip: {value}",
+                    "always_visible": True,
+                    "style": {"padding": "8px"},
+                },
+            ),
+            dcc.RangeSlider(
+                value=[48, 60],
+                min=20,
+                max=100,
+                id="range-slider",
+                tooltip={"template": "Custom tooltip: {value}", "always_visible": True},
+            ),
+            dcc.Slider(
+                min=20,
+                max=100,
+                id="slider-transform",
+                tooltip={"always_visible": True, "transform": "transformTooltip"},
+            ),
+        ],
+        style={"padding": "12px", "marginTop": "48px"},
+    )
+
+    dash_dcc.start_server(app)
+    # dash_dcc.wait_for_element("#slider")
+
+    dash_dcc.wait_for_text_to_equal(
+        "#slider .rc-slider-tooltip-content", "Custom tooltip: 34"
+    )
+    dash_dcc.wait_for_text_to_equal(
+        "#range-slider .rc-slider-tooltip-content", "Custom tooltip: 48"
+    )
+    dash_dcc.wait_for_text_to_equal(
+        "#range-slider > div:nth-child(1) > div:last-child .rc-slider-tooltip-content",
+        "Custom tooltip: 60",
+    )
+    dash_dcc.wait_for_style_to_equal(
+        "#slider .rc-slider-tooltip-inner > div", "padding", "8px"
+    )
+    dash_dcc.wait_for_text_to_equal(
+        "#slider-transform .rc-slider-tooltip-content", "Transformed 20"
+    )
+
+    dash_dcc.percy_snapshot("sliders-format-tooltips")
+
+    assert dash_dcc.get_logs() == []