Why is structured (JSON) logging generally preferred over plain-text console.log() statements in a production Node.js application?

Structured logging outputs each log entry as a machine-parseable object (typically JSON) with consistent fields (timestamp, level, message, and contextual metadata) rather than a free-form text string -- this makes logs searchable, filterable, and aggregatable by a centralized logging system (like an ELK stack or Datadog), letting you query for 'all error-level logs for user X in the last hour' precisely, something that's difficult and fragile with unstructured plain-text logs relying on regex parsing.

// Unstructured: hard to search/filter reliably at scale
console.log('User ' + userId + ' logged in at ' + new Date());

// Structured: easily queryable by any field
const pino = require('pino')();
pino.info({ event: 'user_login', userId, timestamp: Date.now() }, 'User logged in');