Expression Helper Functions

Expression helper functions give you safe nested-property access, null coalescing, JSON serialization, URL encoding, and conditionals -- the utilities you reach for after get() and set() are not enough.

Overview

Function	Purpose
json(data)	Convert data to JSON string
toJSON(data)	Alias for json()
safe(obj, path)	Safely access nested properties
debug(obj)	Format data for debugging
default(value, fallback)	Null coalescing
urlencode(str)	URL-encode a string
ternary(cond, trueVal, falseVal)	Conditional expression
input(key)	Access request input
output(resourceId)	Access resource output

json()

Converts any data structure to a JSON string. Useful for logging, debugging, or preparing data for external APIs.

Syntax

json(data)

Parameters

Parameter	Type	Description
data	any	Data to convert to JSON

Examples

Basic usage:

# resources/example.yaml
actionId: formatData
after:
  - set('user', {"name": "Alice", "age": 30})
  - set('userJson', json(get('user')))
  # Result: '{"name":"Alice","age":30}'

Preparing API payload:

# resources/example.yaml
after:
  - set('payload', json({
      "query": get('q'),
      "timestamp": info('timestamp'),
      "metadata": get('sessionData')
    }))
httpClient:
  url: "https://api.example.com/data"
  method: POST
  data: "{{ get('payload') }}"

Logging complex objects:

# resources/example.yaml
after:
  - set('debugLog', json({
      "request": get('q'),
      "response": get('llmResource'),
      "duration": info('timestamp')
    }))

safe()

Safely accesses nested properties without throwing errors. Returns nil if any part of the path is missing.

Syntax

safe(object, path)

Parameters

Parameter	Type	Description
object	object	The object to traverse
path	string	Dot-separated path to the property

Examples

Basic nested access:

# resources/example.yaml
after:
  # If user is {"profile": {"address": {"city": "NYC"}}}
  - set('city', safe(get('user'), 'profile.address.city'))
  # Result: "NYC"

  # If path doesn't exist, returns nil instead of error
  - set('country', safe(get('user'), 'profile.address.country'))
  # Result: nil (no error thrown)

With fallback using default():

# resources/example.yaml
after:
  - set('city', default(safe(get('user'), 'profile.address.city'), 'Unknown'))

Accessing API response data:

# resources/example.yaml
after:
  - set('errorMessage', safe(get('apiResponse'), 'error.details.message'))
  - set('items', safe(get('apiResponse'), 'data.items'))

Handling optional configuration:

# resources/example.yaml
after:
  - set('timeout', default(safe(get('config'), 'http.timeout'), 30))
  - set('retries', default(safe(get('config'), 'http.retries'), 3))

debug()

Returns a formatted, indented JSON string representation of any data. Useful for development and troubleshooting.

Syntax

debug(data)

Parameters

Parameter	Type	Description
data	any	Data to format for debugging

Examples

Debug LLM response:

# resources/example.yaml
after:
  - set('debugInfo', debug(get('llmResource')))
  # Result (formatted with indentation):
  # {
  #   "response": "...",
  #   "model": "llama3.2:1b",
  #   "tokens": 150
  # }

Debug request context:

# resources/example.yaml
after:
  - set('requestDebug', debug({
      "query": get('q'),
      "headers": get('Authorization'),
      "session": get('userId', 'session')
    }))

Include in API response for debugging:

# resources/example.yaml
apiResponse:
  success: true
  response:
    data: get('result')
    _debug: "{{ get('debugInfo') }}"  # Remove in production

default()

Null coalescing operator. Returns the fallback value if the primary value is nil or an empty string.

Syntax

default(value, fallback)

Parameters

Parameter	Type	Description
value	any	Primary value to check
fallback	any	Value to return if primary is nil/empty

Examples

Basic fallback:

# resources/example.yaml
after:
  - set('name', default(get('userName'), 'Guest'))
  - set('limit', default(get('pageSize'), 10))

Chained defaults:

# resources/example.yaml
after:
  # Try multiple sources in order
  - set('apiKey', default(
      get('API_KEY', 'env'),
      default(
        get('apiKey', 'session'),
        'default-key'
      )
    ))

With safe() for nested access:

# resources/example.yaml
after:
  - set('email', default(safe(get('user'), 'contact.email'), 'no-email@example.com'))

Configuration defaults:

# resources/example.yaml
after:
  - set('config', {
      "timeout": default(get('timeout'), 30),
      "retries": default(get('retries'), 3),
      "model": default(get('model'), 'llama3.2:1b')
    })

toJSON()

Alias for json(). Converts any data structure to a JSON string.

Syntax

toJSON(data)

urlencode()

URL-encodes a string. Useful for building query parameters or form-encoded values.

Syntax

urlencode(str)

Examples

# resources/example.yaml
component:
  name: browser
  with:
    url: "https://www.example.com/search?q={{ urlencode(get('query')) }}"
    action: getText

# resources/example.yaml
after:
  - set('encoded', urlencode(get('searchTerm')))
  # "hello world" -> "hello+world"

ternary()

Returns trueVal if cond is true, otherwise returns falseVal. Equivalent to a conditional expression.

Syntax

ternary(condition, trueVal, falseVal)

Parameters

Parameter	Type	Description
condition	bool	Boolean condition to test
trueVal	any	Value returned when condition is true
falseVal	any	Value returned when condition is false

Examples

# resources/example.yaml
component:
  name: browser
  with:
    url: "https://example.com/jobs?remote={{ ternary(get('remote_only') == 'true', '2', '') }}"
    action: getText

# resources/example.yaml
after:
  - set('label', ternary(get('isAdmin'), 'Admin', 'User'))

input()

Alternative way to access request input parameters. Equivalent to get(key) for request data.

Syntax

input(key)
# or
input.property

Parameters

Parameter	Type	Description
key	string	The input parameter name

Examples

Function style:

# resources/example.yaml
after:
  - set('query', input('q'))
  - set('limit', input('limit'))

Property access style:

# resources/example.yaml
after:
  - set('items', input.items)
  - set('userId', input.userId)

Equivalent to get():

# resources/example.yaml
after:
  # These are equivalent:
  - set('query1', get('q'))
  - set('query2', input('q'))

output()

Alternative way to access resource outputs. Equivalent to get(resourceId).

Syntax

output(resourceId)

Parameters

Parameter	Type	Description
resourceId	string	The actionId of the resource

Examples

Basic usage:

# resources/example.yaml
after:
  - set('llmResult', output('llmResource'))
  - set('sqlData', output('databaseQuery'))

Equivalent to get():

# resources/example.yaml
after:
  # These are equivalent:
  - set('result1', get('llmResource'))
  - set('result2', output('llmResource'))

See Also

• Unified API - Core get() and set() functions
• Expressions - Expression syntax and operators
• Expression Functions Reference - Complete function reference with array, string, and type operations
• Items Iteration - Processing multiple items