validate environment variables early

Environment variables should be validated at startup or module initialization rather than at runtime usage. Use non-null assertion operators or explicit validation checks to fail fast when required configuration is missing, preventing delayed runtime errors and making configuration issues immediately apparent during development and deployment.

Instead of logging errors and continuing execution:

const url = process.env.SEARXNG_ENDPOINT as string;
if (!url) {
  console.error(`SEARXNG_ENDPOINT environment variable is not set`);
}
// Code continues and may fail later...

Use non-null assertion for required variables:

const url = process.env.SEARXNG_ENDPOINT!;

Or implement explicit validation at module initialization:

if (!process.env.SEARXNG_ENDPOINT) {
  throw new Error('SEARXNG_ENDPOINT environment variable is required');
}

This approach ensures configuration problems are caught early in the application lifecycle rather than causing mysterious runtime failures.