Add export mermaid feature

Author: tasnim0tantawi

src/components/EditorHeader/ControlPanel.jsx

@@ -29,6 +29,7 @@ import {
   jsonToSQLite,
   jsonToMariaDB,
   jsonToSQLServer,
+  jsonToMermaid,
 } from "../../utils/exportSQL/generic";
 import {
   ObjectType,
@@ -1012,6 +1013,25 @@ export default function ControlPanel({
               saveAs(blob, `${exportData.filename}.ddb`);
             },
           },
+          {
+            MERMAID: () => {
+              setModal(MODAL.CODE);
+              const result = jsonToMermaid({
+                tables: tables,
+                relationships: relationships,
+                notes: notes,
+                subjectAreas: areas,
+                database: database,
+                title: title,
+              });
+              // generate .md file
+              setExportData((prev) => ({
+                ...prev,
+                data: result,
+                extension: "md",
+              }));
+            },
+          },
         ],
         function: () => {},
       },

src/utils/exportSQL/generic.js

@@ -502,3 +502,41 @@ export function jsonToSQLServer(obj) {
     )
     .join("\n")}`;
 }
+
+export function jsonToMermaid(obj) {
+  function getMermaidRelationship(relationship) {
+    switch (relationship) {
+      case "One to one":
+        return "||--||";
+      case "One to many":
+        return "||--o{";
+      case "Many to one":
+        return "}o--||";
+      default:
+        return "--";
+    }
+  }
+  const mermaidEntities = obj.tables
+    .map((table) => {
+      const fields = table.fields
+        .map((field) => {
+          const fieldType = getTypeString(field, obj.database, "mssql");
+          return `        ${fieldType} ${field.name}`;
+        })
+        .join("\n");
+      return `    ${table.name} {\n${fields}\n    }`;
+    })
+    .join("\n\n");
+
+  const mermaidRelationships = obj.relationships?.length
+    ? obj.relationships
+        .map((r) => {
+          const startTable = obj.tables[r.startTableId].name;
+          const endTable = obj.tables[r.endTableId].name;
+          return `    ${startTable} ${getMermaidRelationship(r.cardinality)} ${endTable} : references`;
+        })
+        .join("\n")
+    : "";
+
+  return `erDiagram\n${mermaidRelationships ? `${mermaidRelationships}\n\n` : ""}${mermaidEntities}`;
+}