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• Collapsible Indented Tree in Angular Example


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I already have the Tree up and running where all my logic is written within ngAfterViewInit() Hook.

The code works well. However I wish to add Collapse All and Expand All button globally so that a User can use them accordingly without painstakingly click on all the nodes either to collapse or expand the complete tree.

Unfortunately, I have no class methods or variables that are public within the component. This limits the method calls to the buttons:

 <button (click)="expandAll()"></button> <!-- expandAll() has nothing to trigger as a parameter-->

hello.component.ts

export class HelloComponent  {

  @Input() name: string;



  ngAfterViewInit(): void {

    let margin = {top: 30, right: 10, bottom: 30, left: 20};

    let width = 960;

    let barHeight = 20;

    let barWidth = (width - margin.left - margin.right) * 0.8;



    let i = 0, duration = 400, root;

    let diagonal = d3.linkHorizontal()

        .x((d) => { return d.y; })

        .y((d) => { return d.x; });



    let svg = d3.select(".tree").append("svg")

      .attr("width", width) //+ margin.left + margin.right)

      .append("g")

      .attr("transform", "translate(" + margin.left + "," + margin.top + ")");





    root = d3.hierarchy(flares);

    root.x0 = 0;

    root.y0 = 0;

    moveChildren(root);

    update(root);



    function update(source) {



      // Compute the flattened node list.

      let nodes = root.descendants();



      let height = Math.max(500, nodes.length * barHeight + margin.top + margin.bottom);



      d3.select("svg").transition()

          .duration(duration)

          .attr("height", height);



      d3.select(self.frameElement).transition()

          .duration(duration)

          .style("height", height + "px");



      // Compute the "layout". TODO https://github.com/d3/d3-hierarchy/issues/67

      let index = -1;

      root.eachBefore(function(n) {

        n.x = ++index * barHeight;

        n.y = n.depth * 20;

      });



      // Update the nodes…

      let node = svg.selectAll(".node")

        .data(nodes, function(d) { return d.id || (d.id = ++i); });



      let nodeEnter = node.enter().append("g")

          .attr("class", "node")

          .attr("transform", function(d) { return "translate(" + source.y0 + "," + source.x0 + ")"; })

          .style("opacity", 0);



      // Enter any new nodes at the parent's previous position.

      nodeEnter.append("rect")

          .attr("y", -barHeight / 2)

          .attr("height", barHeight)

          .attr("width", barWidth)

          .style("fill", color)

          .on("click", click);



      nodeEnter.append("text")

          .attr("dy", 3.5)

          .attr("dx", 5.5)

          .text(function(d) { return d.data.name; });



      // Transition nodes to their new position.

      nodeEnter.transition()

          .duration(duration)

          .attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; })

          .style("opacity", 1);



      node.transition()

          .duration(duration)

          .attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; })

          .style("opacity", 1)

        .select("rect")

          .style("fill", color);



      // Transition exiting nodes to the parent's new position.

      node.exit().transition()

          .duration(duration)

          .attr("transform", function(d) { return "translate(" + source.y + "," + source.x + ")"; })

          .style("opacity", 0)

          .remove();



      // Stash the old positions for transition.

      root.each(function(d) {

        d.x0 = d.x;

        d.y0 = d.y;

      });

    }



  // Toggle children on click.

    function click(d) {

      if (d.children) {

        d._children = d.children;

        d.children = null;

      } else {

        d.children = d._children;

        d._children = null;

      }

      update(d);

    }



    function color(d) {

      return d._children ? "#3182bd" : d.children ? "#c6dbef" : "#fd8d3c";

    }



    function moveChildren(node) { // https://stackoverflow.com/questions/19423396/d3-js-how-to-make-all-the-nodes-collapsed-in-collapsible-indented-tree

    if(node.children) {

        node.children.forEach(function(c) { moveChildren(c); });

        node._children = node.children;

        node.children = null;

      }

    }

  }

}

References

Expand All/Collapse All d3-tree provides some logic but it requires me to use root variable which in fact is only local to ngAfterViewInit()Hook and might not be accessible for other class methods.

How do I achieve this?