Handlebars - Best Practices

When adding Handlebars, there are some Best Practices to keep in mind:

• Always provide fallbacks: 
  • Use default or or helpers to ensure graceful degradation when data is missing.
    • Hello {{or [First-Name] "Valued Customer"}}!
• Wrap complex variables: 
  • Any variable name with special characters (hyphens, colons, spaces) must be wrapped in square brackets:
    • {{[First-Name]}} Correct (has hyphen)
    • {{[todaysdate:Ymd]}} Correct (has colon)
    • {{[subscriber-timezone]}} Correct (has hypen)
    • {{First-Name}} Incorrect (should be wrapped in square brackets)
• Variables with underscores only (like current_day, subscriber_id) do NOT need brackets:
  • {{current_day}} Correct (has underscore)
  • {{[random_number]}} Incorrect (square brackets not required)
• Test with empty data 
  • ​​Ensure your templates render correctly when custom fields are empty.
• Use meaningful fallbacks 
  • ​​Instead of generic "Customer", try context-specific fallbacks:
    Hello {{or [First-Name] "Valued member"}}!
• Combine helpers for complex logic: 
  • Nest helpers to create sophisticated conditional logic:
    • {{#if (and (eq [Country] "US") (gt [Order-Total] 50))}
• Keep comparisons data type-appropriate: 
  • Use gt and ltonly with numeric values.
    • {{#if (lt [Days-Until-Expiration] 7)}}  <p><strong>URGENT:</strong> Your membership expires in {{[Days-Until-Expiration]}} days!</p> {{/if}}

If your Handlebars aren't quite working how you'd like them to, here are some ways you can troubleshoot common problems that arise.

• Issue: Variable not displaying
  • Solution: Check if the variable name has special characters (hyphens, colons, spaces) and wrap it in brackets 
    • {{[First-Name]}}, {{[todaysdate:Ymd]}}
  • Note: Variables with only underscores don't need brackets
    
    • {{current_day}}, {{subscriber_id}}
• Issue: Comparison not working
  • Solution: Ensure you're comparing compatible types (numbers with numbers, strings with strings)
• Issue: Syntax errors
  • Solution: Verify all opening {{#if}} tags have closing {{/if}} tags
• Issue: gt or lt not working
  • Solution: These helpers only work with numeric values. Ensure your custom fields contain numbers.