Fully featured eCharts

flexcharts adapter for ioBroker

Bring the full power of Apache ECharts to ioBroker — without any limitations imposed by a graphical configuration UI.

This adapter is aimed at experienced users. There is no UI to configure charts. You define charts entirely in code (JavaScript or Blockly) or as JSON stored in an ioBroker state.

Take a look at the ECharts demo gallery to get an idea of what's possible.

Remark: Adapter was not tested on MacOS, yet.

What's new in v0.7.3

Configurable timeout for source=script widgets — avoids false timeout errors for computation-heavy or coordinated/serial chart setups:

• New optional &requestTimeout=<ms> parameter overrides the default 2000 ms wait for the script's onMessage() response
• Default behavior is unchanged — only relevant if you actually hit the timeout

What's new in v0.7.2

Beginner-friendly templates and step-by-step Cookbook — making flexcharts more accessible for users new to ECharts:

• Two new beginner-friendly templates: template6 (energy stacked bar with history adapter data) and template7 (reactive gauge chart with SSE auto-update)
• Improved comments and STEP markers across all existing templates (1–5)
• New Wiki with Cookbook: step-by-step guides for building live charts from scratch — see Further Examples and Resources

What's new in v0.7.1

SSE chart updates without page reload — when using &sse, the chart now updates in place instead of reloading the full page:

• ECharts animations run smoothly on every data update
• No flickering or chart rebuild on refresh
• Works transparently for all existing &sse URLs — no changes needed

How it works

Other ioBroker chart adapters use a UI to configure chart content and options — which typically limits what you can express. flexcharts takes a different approach:

1. You define the chart as a JSON object (the ECharts option variable) — either stored in an ioBroker state or returned from a JavaScript script.
2. flexcharts passes that definition to Apache ECharts in the browser and renders it.

Example — a stacked bar chart stored as a state value:

{ "tooltip": {"trigger": "axis","axisPointer": {"type": "shadow"}},
  "legend": {},
  "xAxis": [{"type": "category","data": ["Mon","Tue","Wed","Thu","Fri","Sat","Sun"]}],
  "yAxis": [{"type": "value"}],
  "dataZoom": [{"show": true,"start": 0, "end": 100}],
  "series": [
    { "name": "Grid",      "type": "bar", "color": "#a30000", "stack": "Supply",      "data": [8,19,21,50,26,0,36]},
    { "name": "PV",        "type": "bar", "color": "#00a300", "stack": "Supply",      "data": [30,32,20,8,33,21,36]},
    { "name": "Household", "type": "bar", "color": "#0000a3", "stack": "Consumption", "data": [16,12,11,13,14,9,12]},
    { "name": "Heat pump", "type": "bar", "color": "#0000ff", "stack": "Consumption", "data": [22,24,30,20,22,12,25]},
    { "name": "Wallbox",   "type": "bar", "color": "#00a3a3", "stack": "Consumption", "data": [0,15,0,25,23,0,35]}
  ]
}

Result:

Prerequisites

flexcharts runs as a web extension. The web adapter (web.0) must be installed and running. The examples below assume the default port 8082.

Getting started

Verify installation

Open this URL in a browser (replace localhost with your ioBroker server address):

http://localhost:8082/flexcharts/echarts.html?source=state&id=flexcharts.0.info.chart1

A demo chart should appear. If it does, the adapter is working correctly.

Source option 1 — ioBroker state

http://localhost:8082/flexcharts/echarts.html?source=state&id=0_userdata.0.echarts.chart1

flexcharts reads the state 0_userdata.0.echarts.chart1 and renders it as an EChart. Create this state, paste the JSON example from above as its value, then open the URL.

Note: These characters are not allowed in state IDs: : / ? # [ ] @ ! $ & ' ( ) * + , ; = %

Source option 2 — JavaScript script

This is more flexible. flexcharts calls your script on each request and your script returns the chart definition. Additional URL parameters are forwarded to the script.

Only javascript.0 (the first JS adapter instance) is supported.

Create a script:

onMessage('flexcharts', (httpParams, callback) => {
    const myJsonParams = (httpParams.myjsonparams ? JSON.parse(httpParams.myjsonparams) : {});
    console.log(`httpParams = ${JSON.stringify(httpParams)}`);
    chart1(result => callback(result));
});

function chart1(callback) {
    const option = {
        tooltip: {trigger: "axis", axisPointer: {type: "shadow"}},
        legend: {},
        xAxis: [{type: "category", data: ["Mon","Tue","Wed","Thu","Fri","Sat","Sun"]}],
        yAxis: [{type: "value"}],
        dataZoom: [{show: true, start: 0, end: 100}],
        series: [
            {name: "Grid",      type: "bar", color: "#a30000", stack: "Supply",      data: [8,19,21,50,26,0,36]},
            {name: "PV",        type: "bar", color: "#00a300", stack: "Supply",      data: [30,32,20,8,33,21,36]},
            {name: "Household", type: "bar", color: "#0000a3", stack: "Consumption", data: [16,12,11,13,14,9,12]},
            {name: "Heat pump", type: "bar", color: "#0000ff", stack: "Consumption", data: [22,24,30,20,22,12,25]},
            {name: "Wallbox",   type: "bar", color: "#00a3a3", stack: "Consumption", data: [0,15,0,25,23,0,35]}
        ]
    };
    callback(option);
}

Start the script, then open: http://localhost:8082/flexcharts/echarts.html?source=script

The default message name is flexcharts. To use a different name add &message=mycharts and adjust onMessage('mycharts', ...) accordingly.

Extra URL parameters are passed through to the script in httpParams:

http://localhost:8082/flexcharts/echarts.html?source=script&chart=chart1&myjsonparams={"period":"daily"}

Advanced features

JavaScript functions inside chart definitions

Standard JSON.stringify() strips functions from chart definitions. To include functions (e.g. custom formatters), use the npm module javascript-stringify:

1. Add javascript-stringify to "Additional npm modules" in the javascript adapter configuration:
2. In your script: var strify = require('javascript-stringify');
3. Replace callback(option) with callback(strify.stringify(option)) — or for a state: setState('my_chart_id', strify.stringify(option), true)

See template3 for a working example using a tooltip formatter.

Security note: javascript-stringify enables passing arbitrary code to the browser. Do not expose ioBroker to the Internet when using this module.

Event-driven dynamic charts

ECharts supports interactive charts that update in response to user actions. See this ECharts example and a screen recording with flexcharts.

Use a script as source and pass chart definition and event handlers as an array. Template 4 demonstrates this. Key rules:

• Event handlers must use myChart.on("event", function(e){ ... })
• The handler must be a JavaScript string (use consistent quoting, or minify with a JS minifier)
• Pass everything as an array: callback([strify.stringify(option), onEvent1, onEvent2])

With a state as source, the state must be a JSON array of strings. Both the chart definition and the handler strings must be valid JSON strings (no newlines, only escaped quotes inside). Example: flexcharts.0.info.chart3.

Note for users upgrading from v0.4.x: The chart options variable was renamed from jsopts to option in v0.5.0. Update your event handler functions accordingly.

Security note: Same as above — do not expose ioBroker to the Internet when using javascript-stringify.

Event-triggered chart refresh (SSE)

Add &sse to any chart URL to enable automatic chart updates via Server-Sent Events. The browser keeps a persistent connection to the server and updates the chart in place whenever the source data changes — no page reload, no polling interval needed. ECharts animations run smoothly on every update.

With source=state:

The chart updates automatically whenever the state specified by &id= changes.

http://localhost:8082/flexcharts/echarts.html?source=state&id=0_userdata.0.echarts.chart1&sse

With source=script:

The script controls the chart content, so flexcharts cannot know which state triggers a refresh. Specify it explicitly with &triggerid=<state_id>:

http://localhost:8082/flexcharts/echarts.html?source=script&message=mycharts&triggerid=0_userdata.0.echarts.trigger&sse

The chart updates whenever 0_userdata.0.echarts.trigger changes. Your ioBroker script can update that state to push chart updates to the browser.

Throttle and ack filter:

By default (&sse without value) the chart updates at most once every 5 seconds (minimum). Pass a number to set a longer minimum interval:

...&sse=30    → update at most once every 30 seconds

For fine-grained control use a JSON object (URL-encoded):

...&sse={"refresh":10,"ack":true}   → update only on acknowledged state changes, at most every 10 s
...&sse={"ack":false}               → update only on unacknowledged changes (set by script), default interval

State changes during the throttle interval are not lost — the update is deferred to the next allowed moment.

Note: &sse and &refresh can be combined — SSE triggers an in-place update on state change, &refresh provides a fallback periodic page reload.

Themes (ECharts v6)

Use the Apache ECharts Theme Builder to create or modify themes.

Using a script as source:

1. Download theme from Theme Builder → tab "JSON version" → Copy
2. In your script: const myThemeDefault = <paste here>
3. Pass it as part of the callback array: callback([JSON.stringify(option), ['default', JSON.stringify(myThemeDefault)]])

Template 5 shows full theme switching including dark mode.

Using a state as source:

The state value must be an array: [<stringified chart>, ['default', <stringified theme>]]. See flexcharts.0.info.chart4 for a working example.

Themes other than default and dark require explicit activation via myChart.setTheme(<name>) inside an event-driven function.

Quick try:

callback([JSON.stringify(option), ['default', '{"title":{"left":"left"},"color":["#ff715e","#ffaf51","#ffee51","#8c6ac4","#715c87"],"backgroundColor":"rgba(64,64,64,0.5)"}']]);

Templates

Further Examples and Resources

Cookbook (step-by-step guides)

New to flexcharts or ECharts? The flexcharts Wiki provides step-by-step cookbook articles that guide you from a static chart to a fully live, interactive dashboard:

More cookbook articles are planned.

Third-party adapter examples

• tibberLink adapter: see discussions here and here — tibberLink also uses flexcharts natively, see its documentation
• sun2000 adapter: native integration of flexcharts is available
• Viessmann E3 series (e.g. Vitocal 250 heat pump): ioBroker.e3oncan discussion

Reference

Base URL: http://localhost:8082/flexcharts/echarts.html

Donate

If you enjoyed this project — or just feeling generous, consider buying me a beer. Cheers! :beers:

Changelog

0.7.3 (2026-08-24)

• (MyHomeMyData) Added optional requestTimeout parameter for source=script widgets to configure the timeout waiting on the script's response (default 2000 ms, unchanged). Ref. issue #205

0.7.2 (2026-05-07)

• (MyHomeMyData) Added beginner-friendly templates 6 (energy stacked bar chart with history adapter) and 7 (reactive gauge chart with SSE auto-update)
• (MyHomeMyData) Improved comments and STEP markers in templates 1–5
• (MyHomeMyData) Added Wiki with Cookbook articles A1–A3 (step-by-step guides for building live charts)

0.7.1 (2026-05-05)

• (MyHomeMyData) Adapter requires node.js >= 22 now
• (MyHomeMyData) SSE now updates chart in place via setOption instead of reloading the page — ECharts animations work correctly on data updates

0.7.0 (2026-04-15)

• (MyHomeMyData) Implemented SSE (Server-Sent Events) to support event driven updating of chart

0.6.2 (2026-04-13)

• (MyHomeMyData) Restructuring of code for better readability and improved performance.
• (MyHomeMyData) Restructuring of Readme for better readability.

Older versions

Older changelog entries are available in CHANGELOG_OLD.md.

License

MIT License

Copyright (c) 2024-2026 MyHomeMyData juergen.bonfert@gmail.com

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Additional remark: Source code of Apache ECharts is used according to Apache License, Version 2.0