Pipes Guide

Overview

Pipes validate and transform input data before it reaches your tool handler.

Creating a Pipe

import { Pipe, PipeInterface } from 'nitrostack';

@Pipe()
export class ValidationPipe implements PipeInterface {
  transform(value: any, metadata?: any): any {
    // Validate and transform
    if (!value || typeof value !== 'object') {
      throw new Error('Invalid input: must be an object');
    }
    
    return value;
  }
}

Using Pipes

@Tool({ name: 'create_user' })
@UsePipes(ValidationPipe, TransformPipe)
async createUser(input: any, ctx: ExecutionContext) {
  // Input has been validated and transformed
}

Pipe Examples

Trim Strings

@Pipe()
export class TrimPipe implements PipeInterface {
  transform(value: any): any {
    if (typeof value === 'string') {
      return value.trim();
    }
    
    if (Array.isArray(value)) {
      return value.map(item => this.transform(item));
    }
    
    if (value && typeof value === 'object') {
      const trimmed: any = {};
      for (const [key, val] of Object.entries(value)) {
        trimmed[key] = this.transform(val);
      }
      return trimmed;
    }
    
    return value;
  }
}

Parse Integers

@Pipe()
export class ParseIntPipe implements PipeInterface {
  transform(value: any): number {
    const parsed = parseInt(value, 10);
    
    if (isNaN(parsed)) {
      throw new Error(`Cannot parse "${value}" as integer`);
    }
    
    return parsed;
  }
}

Next Steps

• Tools Guide
• Validation