transform_code
Execute multiple JavaScript/TypeScript code transformations in one operation, such as renaming, replacing, or inserting code, to streamline complex refactoring and migration tasks.
Instructions
Apply multiple transformations in a single operation. Most powerful tool for complex refactoring workflows.
Examples: • API refactor: [{type: 'rename', parameters: {oldName: 'getData', newName: 'fetchData'}}, {type: 'removeUnusedImports'}] • Environment update: [{type: 'replaceIn', parameters: {nodeType: 'string', pattern: /localhost/g, replacement: 'api.production.com'}}, {type: 'removeUnusedImports'}] • Add logging: [{type: 'insertAfter', parameters: {pattern: 'function_declaration', text: 'console.log("Function called");'}}, {type: 'removeUnusedImports'}] • Bulk rename: [{type: 'rename', parameters: {oldName: 'user', newName: 'customer'}}, {type: 'rename', parameters: {oldName: 'id', newName: 'customerId'}}] • Legacy migration: [{type: 'replaceIn', parameters: {nodeType: 'call_expression', pattern: /XMLHttpRequest/g, replacement: 'fetch'}}, {type: 'removeUnusedImports'}]
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| operations | Yes | Array of transformation operations applied in sequence. Use preview:true first! | |
| preview | No | Return preview only without applying changes (default: false). ALWAYS preview complex transformations first. |
Input Schema (JSON Schema)
{
"properties": {
"operations": {
"description": "Array of transformation operations applied in sequence. Use preview:true first!",
"items": {
"properties": {
"parameters": {
"description": "Parameters: rename{oldName,newName}, replaceIn{nodeType,pattern,replacement}, insert{pattern,text}",
"type": "object"
},
"type": {
"enum": [
"rename",
"removeUnusedImports",
"replaceIn",
"insertBefore",
"insertAfter"
],
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
},
"type": "array"
},
"preview": {
"description": "Return preview only without applying changes (default: false). ALWAYS preview complex transformations first.",
"type": "boolean"
}
},
"required": [
"operations"
],
"type": "object"
}
Implementation Reference
- src/index.ts:879-958 (handler)The handler function that executes the transform_code tool. It applies a sequence of transformation operations (rename, removeUnusedImports, replaceIn, insertBefore, insertAfter) to the current AST using tree-hugger-js transform API, with preview mode support and error handling.private async transformCode(args: { operations: TransformOperation[]; preview?: boolean }) { if (!this.currentAST) { return { content: [{ type: "text", text: "No AST loaded. Please use parse_code first.", }], isError: true, }; } try { let transformer = this.currentAST.tree.transform(); for (const op of args.operations) { switch (op.type) { case "rename": if (!op.parameters.oldName || !op.parameters.newName) { throw new Error("Rename operation requires oldName and newName parameters"); } transformer = transformer.rename(op.parameters.oldName, op.parameters.newName); break; case "removeUnusedImports": transformer = transformer.removeUnusedImports(); break; case "replaceIn": if (!op.parameters.nodeType || !op.parameters.pattern || !op.parameters.replacement) { throw new Error("ReplaceIn operation requires nodeType, pattern, and replacement parameters"); } transformer = transformer.replaceIn(op.parameters.nodeType, op.parameters.pattern, op.parameters.replacement); break; case "insertBefore": if (!op.parameters.pattern || !op.parameters.text) { throw new Error("InsertBefore operation requires pattern and text parameters"); } transformer = transformer.insertBefore(String(op.parameters.pattern), op.parameters.text); break; case "insertAfter": if (!op.parameters.pattern || !op.parameters.text) { throw new Error("InsertAfter operation requires pattern and text parameters"); } transformer = transformer.insertAfter(String(op.parameters.pattern), op.parameters.text); break; default: throw new Error(`Unknown operation type: ${op.type}`); } } const result = transformer.toString(); if (!args.preview) { this.currentAST.sourceCode = result; this.currentAST.tree = parse(result); this.currentAST.timestamp = new Date(); } const transformResult: TransformResult = { operation: "transform_code", parameters: {}, // TransformOperation parameters don't include operations array preview: result.slice(0, 500) + (result.length > 500 ? '...' : ''), timestamp: new Date(), }; this.transformHistory.push(transformResult); return { content: [{ type: "text", text: `${args.preview ? 'Preview: ' : ''}Applied ${args.operations.length} transformations\n\n${args.preview ? 'Preview:\n' : 'Result:\n'}${result}`, }], }; } catch (error) { return { content: [{ type: "text", text: `Error transforming code: ${error instanceof Error ? error.message : String(error)}`, }], isError: true, }; }
- src/index.ts:317-346 (schema)The input schema definition for the transform_code tool, specifying the operations array with supported types and parameters, plus preview option.name: "transform_code", description: "Apply multiple transformations in a single operation. Most powerful tool for complex refactoring workflows.\n\nExamples:\n• API refactor: [{type: 'rename', parameters: {oldName: 'getData', newName: 'fetchData'}}, {type: 'removeUnusedImports'}]\n• Environment update: [{type: 'replaceIn', parameters: {nodeType: 'string', pattern: /localhost/g, replacement: 'api.production.com'}}, {type: 'removeUnusedImports'}]\n• Add logging: [{type: 'insertAfter', parameters: {pattern: 'function_declaration', text: 'console.log(\"Function called\");'}}, {type: 'removeUnusedImports'}]\n• Bulk rename: [{type: 'rename', parameters: {oldName: 'user', newName: 'customer'}}, {type: 'rename', parameters: {oldName: 'id', newName: 'customerId'}}]\n• Legacy migration: [{type: 'replaceIn', parameters: {nodeType: 'call_expression', pattern: /XMLHttpRequest/g, replacement: 'fetch'}}, {type: 'removeUnusedImports'}]", inputSchema: { type: "object", properties: { operations: { type: "array", items: { type: "object", properties: { type: { type: "string", enum: ["rename", "removeUnusedImports", "replaceIn", "insertBefore", "insertAfter"] }, parameters: { type: "object", description: "Parameters: rename{oldName,newName}, replaceIn{nodeType,pattern,replacement}, insert{pattern,text}" } }, required: ["type"] }, description: "Array of transformation operations applied in sequence. Use preview:true first!" }, preview: { type: "boolean", description: "Return preview only without applying changes (default: false). ALWAYS preview complex transformations first." } }, required: ["operations"], },
- src/index.ts:437-438 (registration)The registration/dispatch case in the CallToolRequestSchema handler that routes calls to the transformCode handler function.case "transform_code": return await this.transformCode(args as { operations: TransformOperation[]; preview?: boolean });
- src/index.ts:316-347 (registration)Tool object registration in the ListToolsRequestSchema response for tool discovery.{ name: "transform_code", description: "Apply multiple transformations in a single operation. Most powerful tool for complex refactoring workflows.\n\nExamples:\n• API refactor: [{type: 'rename', parameters: {oldName: 'getData', newName: 'fetchData'}}, {type: 'removeUnusedImports'}]\n• Environment update: [{type: 'replaceIn', parameters: {nodeType: 'string', pattern: /localhost/g, replacement: 'api.production.com'}}, {type: 'removeUnusedImports'}]\n• Add logging: [{type: 'insertAfter', parameters: {pattern: 'function_declaration', text: 'console.log(\"Function called\");'}}, {type: 'removeUnusedImports'}]\n• Bulk rename: [{type: 'rename', parameters: {oldName: 'user', newName: 'customer'}}, {type: 'rename', parameters: {oldName: 'id', newName: 'customerId'}}]\n• Legacy migration: [{type: 'replaceIn', parameters: {nodeType: 'call_expression', pattern: /XMLHttpRequest/g, replacement: 'fetch'}}, {type: 'removeUnusedImports'}]", inputSchema: { type: "object", properties: { operations: { type: "array", items: { type: "object", properties: { type: { type: "string", enum: ["rename", "removeUnusedImports", "replaceIn", "insertBefore", "insertAfter"] }, parameters: { type: "object", description: "Parameters: rename{oldName,newName}, replaceIn{nodeType,pattern,replacement}, insert{pattern,text}" } }, required: ["type"] }, description: "Array of transformation operations applied in sequence. Use preview:true first!" }, preview: { type: "boolean", description: "Return preview only without applying changes (default: false). ALWAYS preview complex transformations first." } }, required: ["operations"], }, },
- src/index.ts:158-159 (helper)Mention in availableOperations array in the ast://transforms resource."transform_code", "insert_code"