D3 Examples - Force Directed Graph

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<!DOCTYPE html>
<meta charset="utf-8">
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<svg width="960" height="600"></svg>
​
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
var baseNodes = [
    { id: "root", group: -1, label: "Curriculum", level: -1 },
  
  { id: "primary", group: 0, label: "Primary", level: 0 },
    { id: "secondary", group: 0, label: "Secondary", level: 0 },
  { id: "d1", group: 1, label: "Darjah 1", level: 1 },
  { id: "d2", group: 1, label: "Darjah 2", level: 1 },
  { id: "d3", group: 1, label: "Darjah 3", level: 1 },
  { id: "d4", group: 1, label: "Darjah 4", level: 1 },
  { id: "d5", group: 1, label: "Darjah 5", level: 1 },
  { id: "d6", group: 1, label: "Darjah 6", level: 1 },
  
  { id: "t1", group: 1, label: "Tingkatan 1", level: 1 },  
  { id: "t2", group: 1, label: "Tingkatan 2", level: 1 },  
  { id: "t3", group: 1, label: "Tingkatan 3", level: 1 },  
  { id: "t4", group: 1, label: "Tingkatan 4", level: 1 },  
  { id: "t5", group: 1, label: "Tingkatan 5", level: 1 },  
  { id: "t6", group: 1, label: "Tingkatan 6", level: 1 },  
  
  { id: "d1,d2:BI", group: 2, label: "Bahasa Inggeris", level: 2 },    
  { id: "d3:BI", group: 2, label: "Bahasa Inggeris", level: 2 },    
  { id: "d4:BI", group: 2, label: "Bahasa Inggeris", level: 2 },    
  { id: "d5,d6:BI", group: 2, label: "Bahasa Inggeris", level: 2 },
  
  { id: "d1,d2:BI:grammar", group: 3, label: "Grammar", level: 3 },    
  { id: "d1,d2:BI:listening-speaking", group: 3, label: "Listening & Speaking", level: 3 },    
  { id: "d1,d2:BI:literature", group: 3, label: "Literature", level: 3 },    
  { id: "d1,d2:BI:reading", group: 3, label: "Reading", level: 3 },
    { id: "d1,d2:BI:writing", group: 3, label: "Writing", level: 3 },
  
    { id: "d1,d2:BI:grammar", group: 3, label: "Grammar", level: 3 },    
  { id: "d1,d2:BI:listening-speaking", group: 3, label: "Listening & Speaking", level: 3 },    
  { id: "d1,d2:BI:literature", group: 3, label: "Literature", level: 3 },    
  { id: "d1,d2:reading", group: 3, label: "Reading", level: 3 }, 
    { id: "d1,d2:writing", group: 3, label: "Writing", level: 3 }, 
  
    { id: "d3:BI:grammar", group: 3, label: "Grammar", level: 3 },    
  { id: "d3:BI:listening-speaking", group: 3, label: "Listening & Speaking", level: 3 },    
  { id: "d3:BI:literature", group: 3, label: "Literature", level: 3 },    
  { id: "d3:BI:reading", group: 3, label: "Reading", level: 3 }, 
    { id: "d3:BI:writing", group: 3, label: "Writing", level: 3 }, 
  
    { id: "d4:BI:grammar", group: 3, label: "Grammar", level: 3 },    
  { id: "d4:BI:listening-speaking", group: 3, label: "Listening & Speaking", level: 3 },    
  { id: "d4:BI:literature", group: 3, label: "Literature", level: 3 },    
  { id: "d4:BI:reading", group: 3, label: "Reading", level: 3 },
  { id: "d4:BI:writing", group: 3, label: "Writing", level: 3 },
  
{ id: "d5:BI:grammar", group: 3, label: "Grammar", level: 3 },    
  { id: "d5:BI:listening-speaking", group: 3, label: "Listening & Speaking", level: 3 },    
  { id: "d5:BI:literature", group: 3, label: "Literature", level: 3 },    
  { id: "d5:BI:reading", group: 3, label: "Reading", level: 3 },   
    { id: "d5:BI:writing", group: 3, label: "Writing", level: 3 },   
  { id: "d6:BI:grammar", group: 3, label: "Grammar", level: 3 },    
  { id: "d6:BI:listening-speaking", group: 3, label: "Listening & Speaking", level: 3 },    
  { id: "d6:BI:literature", group: 3, label: "Literature", level: 3 },    
  { id: "d6:BI:reading", group: 3, label: "Reading", level: 3 }, 
    { id: "d6:BI:writing", group: 3, label: "Writing", level: 3 }, 
  
  { id: "d1,d2:BM", group: 2, label: "Bahasa Melayu", level: 2 },    
  { id: "d3:BM", group: 2, label: "Bahasa Melayu", level: 2 },    
  { id: "d4:BM", group: 2, label: "Bahasa Melayu", level: 2 },    
  { id: "d5,d6:BM", group: 2, label: "Bahasa Melayu", level: 2 },
  { id: "d6:BM", group: 2, label: "Bahasa Melayu", level: 2 },
  
  { id: "t1,t2:BI", group: 2, label: "Bahasa Inggeris", level: 2 },    
  { id: "t3:BI", group: 2, label: "Bahasa Inggeris", level: 2 },    
  { id: "t4:BI", group: 2, label: "Bahasa Inggeris", level: 2 },    
  { id: "t5,t6:BI", group: 2, label: "Bahasa Inggeris", level: 2 },
  
  { id: "t1,t2:BM", group: 2, label: "Bahasa Melayu", level: 2 },  
  { id: "t3:BM", group: 2, label: "Bahasa Melayu", level: 2 },    
  { id: "t4:BM", group: 2, label: "Bahasa Melayu", level: 2 },    
  { id: "t5,t6:BM", group: 2, label: "Bahasa Melayu", level: 2 },
  { id: "t6:BM", group: 2, label: "Bahasa Melayu", level: 2 }
];
​
var baseLinks = [
  { target: "primary", source: "root", strength: 1},
  { target: "secondary", source: "root", strength: 1},  
  { target: "d1", source: "primary", strength: 1},
  { target: "d2", source: "primary", strength: 1},
  { target: "d3", source: "primary", strength: 1},
  { target: "d4", source: "primary", strength: 1},
  { target: "d5", source: "primary", strength: 1}, 
  { target: "d6", source: "primary", strength: 1},   
  { target: "t1", source: "secondary", strength: 1},
  { target: "t2", source: "secondary", strength: 1},
  { target: "t3", source: "secondary", strength: 1},
  { target: "t4", source: "secondary", strength: 1},
  { target: "t5", source: "secondary", strength: 1}, 
  { target: "t6", source: "secondary", strength: 1},
  
    { target: "d1,d2:BI", source: "d1" , strength: 1 },
    { target: "d1,d2:BI", source: "d2" , strength: 1 },
  { target: "d3:BI", source: "d3" , strength: 1 },
  { target: "d4:BI", source: "d4" , strength: 1 },
  { target: "d5,d6:BI", source: "d5" , strength: 1 },
  { target: "d5,d6:BI", source: "d6" , strength: 1 },
  
  { target: "d1,d2:BI:grammar", source: "d1,d2:BI", strength: 1},
  { target: "d1,d2:BI:listening-speaking", source: "d1,d2:BI", strength: 1},
  { target: "d1,d2:BI:literature", source: "d1,d2:BI", strength: 1},
  { target: "d1,d2:BI:reading", source: "d1,d2:BI", strength: 1},
  { target: "d1,d2:BI:writing", source: "d1,d2:BI", strength: 1},
  
  { target: "d3:BI:grammar", source: "d3:BI", strength: 1},
  { target: "d3:BI:listening-speaking", source: "d3:BI", strength: 1},
  { target: "d3:BI:literature", source: "d3:BI", strength: 1},
  { target: "d3:BI:reading", source: "d3:BI", strength: 1},
  { target: "d3:BI:writing", source: "d3:BI", strength: 1},
  
  
    { target: "d1,d2:BM", source: "d1" , strength: 1 },
    { target: "d1,d2:BM", source: "d2" , strength: 1 },
  { target: "d3:BM", source: "d3" , strength: 1 },
  { target: "d4:BM", source: "d4" , strength: 1 },
  { target: "d5,d6:BM", source: "d5" , strength: 1 },
  { target: "d6:BM", source: "d6" , strength: 1 },
  
    { target: "t1,t2:BI", source: "t1" , strength: 1 },
    { target: "t1,t2:BI", source: "t2" , strength: 1 },
  { target: "t3:BI", source: "t3" , strength: 1 },
  { target: "t4:BI", source: "t4" , strength: 1 },
  { target: "t5,t6:BI", source: "t5" , strength: 1 },
  { target: "t5,t6:BI", source: "t6" , strength: 1 },
  
    { target: "t1,t2:BM", source: "t1" , strength: 1 },
    { target: "t1,t2:BM", source: "t2" , strength: 1 },
  { target: "t3:BM", source: "t3" , strength: 1 },
  { target: "t4:BM", source: "t4" , strength: 1 },
  { target: "t5,t6:BM", source: "t5" , strength: 1 },
  { target: "t6:BM", source: "t6" , strength: 1 }  
]
​
var nodes = [...baseNodes]
var links = [...baseLinks]
​
function getNeighbors(node) {
  return baseLinks.reduce(function (neighbors, link) {
      if (link.target.id === node.id) {
        neighbors.push(link.source.id)
      } else if (link.source.id === node.id) {
        neighbors.push(link.target.id)
      }
      return neighbors
    },
    [node.id]
  )
}
​
function isNeighborLink(node, link) {
  return link.target.id === node.id || link.source.id === node.id
}
​
​
function getNodeColor(node, neighbors) {
  if (Array.isArray(neighbors) && neighbors.indexOf(node.id) > -1) {
    return node.level === 1 ? 'blue' : 'green'
  }
​
  return node.level === 1 ? 'red' : 'gray'
}
​
​
function getLinkColor(node, link) {
  return isNeighborLink(node, link) ? 'green' : '#E5E5E5'
}
​
function getTextColor(node, neighbors) {
  return Array.isArray(neighbors) && neighbors.indexOf(node.id) > -1 ? 'green' : 'black'
}
​
var width = window.innerWidth
var height = window.innerHeight
​
var svg = d3.select('svg')
svg.attr('width', width).attr('height', height)
​
var linkElements,
  nodeElements,
  textElements
​
// we use svg groups to logically group the elements together
var linkGroup = svg.append('g').attr('class', 'links')
var nodeGroup = svg.append('g').attr('class', 'nodes')
var textGroup = svg.append('g').attr('class', 'texts')
​
// we use this reference to select/deselect
// after clicking the same element twice
var selectedId
​
// simulation setup with all forces
var linkForce = d3
  .forceLink()
  .id(function (link) { return link.id })
  .strength(function (link) { return link.strength })
​
var simulation = d3
  .forceSimulation()
simulation.force('link', linkForce)
  .force('charge', d3.forceManyBody().strength(-400))
  .force('center', d3.forceCenter(width / 2, height / 2))
    .force('forceX', d3.forceX())
    .force('forceY', d3.forceY())
​
    simulation.force('forceY')
  .y(height+0.5)
  .strength(0.1)
  simulation.force('forceX')
  .x(width+0.5)
  .strength(0.1);
// select node is called on every click
// we either update the data according to the selection
// or reset the data if the same node is clicked twice
function selectNode(selectedNode) {
  if (selectedId === selectedNode.id) {
    selectedId = undefined
    resetData()
    updateSimulation()
  } else {
    selectedId = selectedNode.id
    updateData(selectedNode)
    updateSimulation()
  }
​
  var neighbors = getNeighbors(selectedNode)
​
  // we modify the styles to highlight selected nodes
  nodeElements.attr('fill', function (node) { return getNodeColor(node, neighbors) })
  textElements.attr('fill', function (node) { return getTextColor(node, neighbors) })
  linkElements.attr('stroke', function (link) { return getLinkColor(selectedNode, link) })
}
​
// this helper simple adds all nodes and links
// that are missing, to recreate the initial state
function resetData() {
  var nodeIds = nodes.map(function (node) { return node.id })
​
  baseNodes.forEach(function (node) {
    if (nodeIds.indexOf(node.id) === -1) {
      nodes.push(node)
    }
  })
​
  links = baseLinks
}
​
// diffing and mutating the data
function updateData(selectedNode) {
  var neighbors = getNeighbors(selectedNode)
  var newNodes = baseNodes.filter(function (node) {
    return neighbors.indexOf(node.id) > -1 || node.level === 1
  })
​
  var diff = {
    removed: nodes.filter(function (node) { return newNodes.indexOf(node) === -1 }),
    added: newNodes.filter(function (node) { return nodes.indexOf(node) === -1 })
  }
​
  diff.removed.forEach(function (node) { nodes.splice(nodes.indexOf(node), 1) })
  diff.added.forEach(function (node) { nodes.push(node) })
​
  links = baseLinks.filter(function (link) {
    return link.target.id === selectedNode.id || link.source.id === selectedNode.id
  })
}
​
function updateGraph() {
  // links
  linkElements = linkGroup.selectAll('line')
    .data(links, function (link) {
      return link.target.id + link.source.id
    })
​
  linkElements.exit().remove()
​
  var linkEnter = linkElements
    .enter().append('line')
    .attr('stroke-width', 1)
    .attr('stroke', 'rgba(50, 50, 50, 0.2)')
​
  linkElements = linkEnter.merge(linkElements)
​
  // nodes
  nodeElements = nodeGroup.selectAll('circle')
    .data(nodes, function (node) { return node.id })
​
  nodeElements.exit().remove()
    var s = d3.scaleOrdinal(d3.schemeCategory20)
  var nodeEnter = nodeElements
    .enter()
    .append('circle')
    .attr('r', function(node) {
                return 18-(node.level*3)
    })
    .attr('fill', function (node) { 
            return s(node.level)
    })
​
  nodeElements = nodeEnter.merge(nodeElements)
​
  // texts
  textElements = textGroup.selectAll('text')
    .data(nodes, function (node) { return node.id })
​
  textElements.exit().remove()
​
  var textEnter = textElements
    .enter()
    .append('text')
    .text(function (node) { return node.label })
    .attr('font-family', 'Helvetica')
    .attr('font-size', 13)
    .attr('fill', '#555555')
    .attr('dx', 15)
    .attr('dy', 4)
​
  textElements = textEnter.merge(textElements)
}
​
function updateSimulation() {
  updateGraph()
​
  simulation.nodes(nodes).on('tick', () => {
    nodeElements
      .attr('cx', function (node) { return node.x })
      .attr('cy', function (node) { return node.y })
    textElements
      .attr('x', function (node) { return node.x })
      .attr('y', function (node) { return node.y })
    linkElements
      .attr('x1', function (link) { return link.source.x })
      .attr('y1', function (link) { return link.source.y })
      .attr('x2', function (link) { return link.target.x })
      .attr('y2', function (link) { return link.target.y })
  })
​
  simulation.force('link').links(links)
//   simulation.alphaTarget(1).restart()
}
​
// last but not least, we call updateSimulation
// to trigger the initial render
updateSimulation()
​
</script>
​
    