ServiceNow Business Rules

Quick start

Basic wrapping pattern (prevents global variable pollution):

(function executeRule(current, previous) {
    // Your code here
})(current, previous);

Execution timing:

Preventing recursion:

// ✓ CORRECT: Direct field assignment in Before rule
current.state = 3; // Auto-saved

// ✗ WRONG: Never use update() in Before/After
current.update(); // Causes loop

Validation pattern

if (current.u_start_date > current.u_end_date) {
    gs.addErrorMessage('Start date must be before end date');
    current.setAbortAction(true); // Blocks DB transaction
}

Best practices

• Use IIFE wrapper for all rules
• Check execution timing before using current.update()
• Refactor complex logic (>10 lines) into Script Includes
• Test recursion prevention on sub-production first
• Use Condition builder in the UI when possible

Key APIs

Reference

For complete execution matrix and advanced patterns, see BEST_PRACTICES.md