Generate enums based on Supabase types

generate-supabase-enums.md

Currently Supabase generates only types by default but it can be useful to have enums. That's how you can do it:

1. Add your own script in package.json e.g. "generate:enums": "node ./scripts/generate-enums.js"

2. Create ./scripts/generate-enums.js file

const fs = require('fs');
const ts = require('typescript');

// Read the types.ts file
const fileContent = fs.readFileSync('./types/supabase.ts', 'utf8');

// Function to transform enum names to PascalCase and remove '_enum' suffix
function transformEnumName(name) {
  return name
    .replace(/_enum$/, '') // Remove '_enum' suffix
    .split('_')
    .map(part => part.charAt(0).toUpperCase() + part.slice(1))
    .join('');
}

// Function to parse and extract enums from Database['public']['Enums']
function extractEnums(content) {
  const sourceFile = ts.createSourceFile('types/supabase.ts', content, ts.ScriptTarget.Latest, true);
  const enums = {};

  function visit(node) {
    if (ts.isPropertySignature(node) &&
      node.name.escapedText === 'Enums' &&
      node.type &&
      ts.isTypeLiteralNode(node.type)) {

      node.type.members.forEach(member => {
        if (ts.isPropertySignature(member) &&
          member.type &&
          ts.isUnionTypeNode(member.type)) {

          const enumName = transformEnumName(member.name.escapedText);
          const enumValues = member.type.types.map(type => {
            if (ts.isLiteralTypeNode(type) && type.literal && ts.isStringLiteral(type.literal)) {
              return type.literal.text;
            }
            return null;
          }).filter(Boolean);

          enums[enumName] = enumValues;
        }
      });
    }

    ts.forEachChild(node, visit);
  }

  visit(sourceFile);

  return enums;
}

// Function to create enum strings
function createEnumStrings(enums) {
  const strs = Object.entries(enums).map(([enumName, enumValues]) => {
    const enumMembers = enumValues.map(
      // sanitize key strs
      value => `${value.toLowerCase()
        .replaceAll(/[^a-zA-Z ]/g, "_")
        .replaceAll(" ", "_")} = "${value}"`)
      .join(',\n  ');
    return `export enum ${enumName} {\n  ${enumMembers}\n}`;
  }).join('\n\n');
  return `// THIS FILE IS AUTO-GENERATED\n\n${strs}`;
}

// Extract enums
const extractedEnums = extractEnums(fileContent);

// Create enum strings
const enumStrings = createEnumStrings(extractedEnums);

// Write enums to a new file
fs.writeFileSync('./types/enums.ts', enumStrings);

3. Enjoy enums.ts file with all your enums (PascalCase, without enum suffix`) - e.g.

export enum LogLevel {
  debug = "debug",
  info = "info",
  warning = "warning",
  error = "error"
}