Utility Helpers

General-purpose template helpers.

Overview

Utility helpers provide common logic for templates, like fallback values and conditional expressions.

or

Return the first truthy value from a list of arguments.

Syntax:

{{or value1 value2 value3 ...}}

Parameters:

• value1, value2, ... - Any number of values to check

Returns: First truthy value, or empty string if all are falsy

Falsy values:

• Empty string ""
• null
• undefined
• false
• 0

Examples

Basic Fallback

{{or pr.assignee "Unassigned"}}

If pr.assignee is empty, returns "Unassigned".

Multiple Fallbacks

{{or pr.assignee pr.author "Default User"}}

Tries pr.assignee, then pr.author, then "Default User".

With Extraction

{{or (extract_from_body "Version: ([\\d.]+)") "Unknown"}}

If extraction returns empty, use "Unknown".

With User Mapping

{{or (map_github_to_asana pr.author) "1234567890"}}

If mapping fails, use fallback GID.

Common Use Cases

Default Task Assignee

create_task:
  assignee: '{{or (map_github_to_asana pr.author) "1234567890"}}'

Assign to mapped user, or default to specific GID.

Default Field Values

update_fields:
  '1234567890': '{{or (extract_from_body "Priority: (\\w+)") "Normal"}}'

Extract priority, or use "Normal" if not found.

Chaining Multiple Sources

update_fields:
  '1234567890': '{{or (extract_from_title "\\[(\\w+)\\]") (extract_from_body "Category: (\\w+)") "Uncategorized"}}'

Try title first, then body, then default.

PR Comment Fallbacks

post_pr_comment: |
  Assigned to: {{or (map_github_to_asana pr.assignee) "No one yet"}}

Complex Logic

create_task:
  title: '{{or (clean_title pr.title) pr.title "Untitled PR"}}'

Use cleaned title, or original title, or default.

Behavior

Empty Strings

Empty strings are falsy:

{{or "" "Fallback"}}
# Returns: "Fallback"

Zero

Zero is falsy:

{{or 0 "Fallback"}}
# Returns: "Fallback"

All Empty

If all values are falsy, returns empty string:

{{or "" null undefined}}
# Returns: ""

Short-Circuit Evaluation

Stops at first truthy value:

{{or "First" "Second"}}
# Returns: "First"
# "Second" never evaluated

Practical Examples

Version with Fallback

rules:
  - when:
      event: pull_request
      action: labeled
      label: 'build_created'
    then:
      update_fields:
        '1234567890': '{{or (extract_from_comments "Version: ([\\d.]+)") "dev"}}'

Assignee Cascade

create_task:
  assignee: '{{or (map_github_to_asana pr.assignee) (map_github_to_asana pr.author) "1234567890"}}'

Priority:

1. PR assignee (if mapped)
2. PR author (if mapped)
3. Default GID

Category Detection

update_fields:
  '1234567890': '{{or (extract_from_title "\\[(\\w+)\\]") (extract_from_body "Category: (\\w+)") "General"}}'

Checks title, then body, then defaults.

Build Information

update_fields:
  '1111111111': '{{or (extract_from_comments "Build #(\\d+)") "Pending"}}'
  '2222222222': '{{or (extract_from_comments "Environment: (\\w+)") "staging"}}'

Task Title Safety

create_task:
  title: '{{or (clean_title pr.title) "PR Update"}}'

Ensures title is never empty.

Combining with Other Helpers

Extraction + OR

'{{or (extract_from_body "Pattern: (\\w+)") "default"}}'

Mapping + OR

'{{or (map_github_to_asana pr.author) "me"}}'

Clean + OR

'{{or (clean_title pr.title) pr.title}}'

Multiple Helpers

'{{or (extract_from_body "Version: ([\\d.]+)") (extract_from_title "v([\\d.]+)") "1.0.0"}}'

Empty Field Updates

Remember: empty template values skip field updates:

# If all values are empty, field update is skipped
update_fields:
  '1234567890': '{{or (extract_from_body "NotFound") (extract_from_title "AlsoNotFound")}}'

This is useful for optional fields.

Debugging

Use in PR comments to see what value is used:

post_pr_comment: |
  Debug:
  - PR Assignee: {{pr.assignee}}
  - PR Author: {{pr.author}}
  - Chosen: {{or pr.assignee pr.author "None"}}

Comparison with Other Languages

Similar to:

• JavaScript: a || b || c
• Python: a or b or c
• Ruby: a || b || c

But returns empty string instead of false or null.

Limitations

No NOT operator

Can't check for "not empty":

# ❌ Can't do this
{{if-not-empty pr.assignee}}

Instead, use conditional rules at the workflow level.

No AND operator

Can't check if multiple values are truthy:

# ❌ Can't do this
{{and pr.assignee pr.author}}

Use separate extractions if needed.

No Complex Logic

For complex logic, use multiple rules:

rules:
  # Rule 1: When assignee exists
  - when:
      event: pull_request
      # Check conditions here
    then:
      # Use pr.assignee

  # Rule 2: When no assignee
  - when:
      event: pull_request
      # Different conditions
    then:
      # Use pr.author

Performance

The or helper is very fast - just checks truthiness. No performance concerns even with many arguments.

See Also

• extract_from_body - Often used with or
• map_github_to_asana - Common or use case
• Context Variables - Available variables
• Template System - Handlebars overview