GraphToMermaid is a python library that turn any graph data structure into mermaid code and vice versa.

Installation

Install with pip:

pip install GraphToMermaid

Quick Start

GraphToMermaid offers a pre-defined graph implementation (DefaultGraph) that works out of the box. Note: DefaultGraph uses NetworkX graph implementation. Converting mermaid code to pre-defined graph:

from adapter.MermaidAdapter import mermaid_to_graph
from adapter.DefaultGraph import DefaultGraph

mermaid_code = """
  flowchart TB
     A --> C
     A --> D
     B --> C
     B --> D
"""

graph = DefaultGraph()
graph = mermaid_to_graph(mermaid_code, graph)
print(graph)

Converting from graph to mermaid code:

from adapter.MermaidAdapter import graph_to_mermaid
from adapter.DefaultGraph import DefaultGraph

graph = DefaultGraph()

graph.add_node("1", "Computer Science")
graph.add_node("2", "Programming")
graph.add_node("3", "Algorithms")

graph.add_edge("1", "2")
graph.add_edge("1", "3")
graph.add_edge("2", "3")

mermaid_code_from_graph = graph_to_mermaid(graph)
print(mermaid_code_from_graph)

Converting from custom graph data structure

GraphToMermaid supports converting from any custom graph data structures. Simply inherits MermaidToGraphAdapter and implements required methods in order to convert mermaid code to graph. And GraphToMermaidAdapter for converting from graph to mermaid.

Example for a custom graph:

class CustomGraph(MermaidAdapter.GraphToMermaidAdapter, MermaidAdapter.MermaidToGraphAdapter):
    def __init__(self):
        self.nodeCollection = {}
        self.next_id = 1

    def add_node(self, name, data=None):
        node_id = self.next_id
        self.next_id += 1
        if node_id not in self.nodeCollection:
            self.nodeCollection[node_id] = CustomNode(node_id, name, data)
        return self.nodeCollection[node_id]

    def remove_node(self, node_id):
        if node_id in self.nodeCollection:
            node = self.nodeCollection[node_id]
            for neighbor in list(node.neighbors):
                node.remove_neighbor(neighbor)
            del self.nodeCollection[node_id]

    def add_edge(self, id1, id2):
        if id1 in self.nodeCollection and id2 in self.nodeCollection:
            node1 = self.nodeCollection[id1]
            node2 = self.nodeCollection[id2]
            node1.add_neighbor(node2)

    def remove_edge(self, id1, id2):
        if id1 in self.nodeCollection and id2 in self.nodeCollection:
            node1 = self.nodeCollection[id1]
            node2 = self.nodeCollection[id2]
            node1.remove_neighbor(node2)

    def get_nodes(self):
        return list(self.nodeCollection.values())

    def get_edges(self):
        edges = set()
        for node in self.nodeCollection.values():
            for neighbor in node.neighbors:
                edge = tuple(sorted([node.id, neighbor.id]))
                edges.add(edge)
        return list(edges)

    def get_node_by_name(self, name):
        for node in self.nodeCollection.values():
            if node.name == name:
                return node
        return None

    def get_node_label_by_id(self, identifier):
        return self.nodeCollection[identifier].name

    def get_node_neighbors_id_by_id(self, identifier):
        return [neighbor.id for neighbor in self.nodeCollection[identifier].neighbors]
    def getAllNodesId(self):
        return list(self.nodeCollection.keys())

    def __str__(self):
        result = "Graph:\n"
        for node in self.nodeCollection.values():
            neighbors = ", ".join(str(neighbor.id) for neighbor in node.neighbors)
            result += f"Node {node.id} ('{node.name}'): {neighbors}\n"
        return result

See examples folder for more