Fast and dirty rollup relay plugin (for use in vite + sveltekit)

rollup-plugin-relay.js

// eslint-disable-next-line @typescript-eslint/explicit-module-boundary-types
export default function relay() {
  return {
    name: 'relay',
    transform(code) {
      // Use indexOf as its probably ;-) faster
      if (code.indexOf('graphql`') > -1) {
        const re = /graphql`[^`]+(?<type>query|fragment|mutation)\s+(?<name>[\w_-\d]+)[^`]+`/gm;

        let imports = [];

        let transformedCode = code.replace(re, (matchStr, _g1, _g2, _pos, _code, groups) => {
          if (groups.type === 'query') {
            const importName = `__graphql__${groups.name}__`;

            imports.push(
              `import ${importName} from '$lib/__generated__/${groups.name}.graphql.ts';`
            );
            return importName;
          }
          // For now we dont support mutations, as we dont use them in svelte project
          // Convert to null preseving lines for sourcemaps to work
          return `null /*${matchStr}*/`;
        });

        if (imports.length > 0) {
          transformedCode += `
            ${imports.join('\n')}
          `;
        }

        return { code: transformedCode };
      }

      return null;
    }
  };
}