intro-github/flow-editor.html at main · jackasser/intro-github · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Flow Editor</title>
  <script src="https://cdn.jsdelivr.net/npm/mermaid/dist/mermaid.min.js"></script>
  <style>
    body { font-family: Arial, sans-serif; margin: 20px; }
    #diagram { border: 1px solid #ccc; padding: 10px; }
    textarea { width: 100%; height: 200px; }
    .controls { margin-top: 10px; }
    .controls input { margin-right: 5px; }
  </style>
</head>
<body>
  <h1>Flow Editor</h1>
  <textarea id="mermaidInput"></textarea>
  <div class="controls">
    <button id="updateBtn">Update</button>
    <button id="saveBtn">Save</button>
    <button id="loadBtn">Load</button>
  </div>
  <div class="controls">
    <input type="text" id="nodeId" placeholder="Node ID">
    <input type="text" id="nodeLabel" placeholder="Node label">
    <button id="addNodeBtn">Add Node</button>
  </div>
  <div class="controls">
    <input type="text" id="fromNode" placeholder="From">
    <input type="text" id="toNode" placeholder="To">
    <input type="text" id="edgeLabel" placeholder="Edge label">
    <button id="addEdgeBtn">Add Edge</button>
  </div>
  <div id="diagram"></div>
  <script>
    mermaid.initialize({ startOnLoad: false });
    const input = document.getElementById('mermaidInput');
    const diagram = document.getElementById('diagram');

    function render() {
      const code = input.value;
      mermaid.render('mermaidDiagram', code, svgCode => {
        diagram.innerHTML = svgCode;
      });
    }

    document.getElementById('updateBtn').addEventListener('click', render);
    document.getElementById('saveBtn').addEventListener('click', () => {
      localStorage.setItem('mermaidFlow', input.value);
    });
    document.getElementById('loadBtn').addEventListener('click', () => {
      input.value = localStorage.getItem('mermaidFlow') || '';
      render();
    });

    document.getElementById('addNodeBtn').addEventListener('click', () => {
      const id = document.getElementById('nodeId').value.trim();
      const label = document.getElementById('nodeLabel').value.trim();
      if (!id) return;
      const lines = input.value.trim().split('\n');
      if (!lines[0]) {
        lines[0] = 'graph LR';
      }
      lines.push(`${id}[${label || id}]`);
      input.value = lines.join('\n');
      document.getElementById('nodeId').value = '';
      document.getElementById('nodeLabel').value = '';
      render();
    });

    document.getElementById('addEdgeBtn').addEventListener('click', () => {
      const from = document.getElementById('fromNode').value.trim();
      const to = document.getElementById('toNode').value.trim();
      const label = document.getElementById('edgeLabel').value.trim();
      if (!from || !to) return;
      const lines = input.value.trim().split('\n');
      if (!lines[0]) {
        lines[0] = 'graph LR';
      }
      if (label) {
        lines.push(`${from} -->|${label}| ${to}`);
      } else {
        lines.push(`${from} --> ${to}`);
      }
      input.value = lines.join('\n');
      document.getElementById('fromNode').value = '';
      document.getElementById('toNode').value = '';
      document.getElementById('edgeLabel').value = '';
      render();
    });

    // load initial
    const stored = localStorage.getItem('mermaidFlow');
    if (stored) {
      input.value = stored;
    } else {
      input.value = `graph LR\nA[Start] --> B[End]`;
    }
    render();
  </script>
</body>
</html>