@ant-design/graphs/es/core/transform/arrange-edge-z-index.js

A React graph library based on Graphin

import { BaseTransform } from '@antv/g6';
/**
 * ArrangeEdgeZIndex transform, specifically for indented tree layout
 */
export class ArrangeEdgeZIndex extends BaseTransform {
    beforeDraw(input) {
        const { model } = this.context;
        const { nodes, edges } = model.getData();
        const oneLevelNodes = nodes.filter((node) => node.depth === 1);
        const oneLevelNodeIds = oneLevelNodes.map((node) => node.id);
        edges.forEach((edge) => {
            if (oneLevelNodeIds.includes(edge.target)) {
                edge.style ||= {};
                edge.style.zIndex = oneLevelNodes.length - oneLevelNodes.findIndex((node) => node.id === edge.target);
            }
        });
        return input;
    }
}