Echarts Streamlit Sync

ECharts Streamlit Sync

Extracts ECharts examples and transforms them into Python code for streamlit-echarts.

Source Discovery

Local Source Extraction (Preferred)

• Repository: ../echarts-examples
• Source files: ../echarts-examples/public/examples/ts/<example-id>.ts
• URL mapping: https://echarts.apache.org/examples/en/editor.html?c=<example-id> → file <example-id>.ts
• Metadata: comment block at top of each file has title, category, titleCN, difficulty

Web Extraction (Fallback)

Only if local source is unavailable. Navigate to the editor URL and extract the option object.

Workflow

1. Extract & Read Source

Given a URL like ?c=pie-padAngle, read ../echarts-examples/public/examples/ts/pie-padAngle.ts.

2. Identify Target File

From the category in the source comment, determine target: demo_echarts/<category>.py.

Existing categories and their files:

bar, boxplot, calendar, candlestick, dataset, events, extensions,
funnel, gauge, graph, heatmap, line, map, parallel, pictorial_bar,
pie, radar, sankey, scatter, sunburst, themeriver, tree, treemap

If the category doesn't have a file yet, create a new demo_echarts/<category>.py and register it in demo_echarts/__init__.py (add to both the imports and ST_DEMOS_BY_CATEGORY).

3. Transform JS → Python

Apply the js-echarts-to-streamlit skill rules. Key reminders:

• JS objects → Python dicts with quoted keys
• true/false/null → True/False/None
• JS functions/gradients → JsCode("...").js_code
• Data logic (loops, map, reduce) → Python equivalents
• Only include properties present in the source — don't add extra grid, tooltip, etc.
• Preserve series as dict or list matching the original

4. Write the Render Function

def render_<descriptive_name>():
    options = { ... }
    st_echarts(options=options, height="500px")

• Function name: render_ + snake_case description derived from the example
• Height: 500px standard, 700px only for exceptionally dense charts
• Import JsCode only if the function uses it
• Import streamlit as st only if using session_state/st.button/st.rerun

5. Register in Demo Dictionary

Add entry to ST_<CATEGORY>_DEMOS dict at bottom of the file:

ST_PIE_DEMOS = {
    ...,
    "Chart Title from Source": (
        render_function_name,
        "https://echarts.apache.org/examples/en/editor.html?c=example-id",
    ),
}

• Dict key: use the title from the source file comment block
• Tuple: (render_function, url_string)
• Placement: user may specify position (e.g., "as first demo", "as second demo"); default to appending at end

6. Verify Conversion

When asked to check an existing conversion:

1. Read both the JS source and the Python function side by side
2. Compare every property — flag any missing, extra, or mismatched values
3. Check gradient colors, data arrays, formatter strings character by character
4. Report findings concisely: what matches, what differs

Interactive Charts (Drilldown Pattern)

For examples using myChart.on('click', ...) with setOption for drill-down:

• Use st.session_state to track current view state
• Use events param to capture clicks: events = {"click": "function(params) { return ... }"}
• Check result.chart_event to update state and st.rerun()
• Use st.button("Back") instead of graphic onclick handlers
• Omit universalTransition (doesn't work across Streamlit reruns)
• Always use key= param on st_echarts for stateful charts

New Category Checklist

When adding a category that doesn't exist yet:

1. Create demo_echarts/<category>.py with render function + ST_<CATEGORY>_DEMOS dict
2. In demo_echarts/__init__.py:
   • Add from .<category> import ST_<CATEGORY>_DEMOS
   • Add "Display Name": ST_<CATEGORY>_DEMOS to ST_DEMOS_BY_CATEGORY