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When to use these helpers

Use a conversion only after you understand the source value. A conversion can make an expression readable, but it cannot repair missing or incorrectly structured source data.

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Calling style

Call a helper as isEmpty($.optional_note). Not every helper is available everywhere: validation, form, and document-template helpers have distinct context contracts. Editor suggestions are not proof that a helper is supported at runtime.

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Complete function reference

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contains

Checks if a string or array contains a specified substring Signature: contains(strOrArr, substring) Example:
Note: It can also be written as a transform when the first value is the input: value | contains(...).

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indexOf

Finds the index of the first occurrence of a substring in a string Signature: indexOf(str, substring) Example:
Note: It can also be written as a transform when the first value is the input: value | indexOf(...).

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isEmpty

Checks a falsy value, an empty array, or a trimmed empty text value. Do not pass a non-text object; use an explicit null/property check instead. Signature: isEmpty(value) Example:
Availability: General helper in shared builder and document-template runtimes; function and transform forms are available. Note: It can also be written as a transform when the first value is the input: value | isEmpty(...).

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isNotEmpty

Negates the active common isEmpty behavior. Use explicit null/array/text tests for a non-text object. Signature: isNotEmpty(value) Example:
Availability: General helper in shared builder and document-template runtimes; function and transform forms are available. Note: It can also be written as a transform when the first value is the input: value | isNotEmpty(...).

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lastIndexOf

Finds the index of the last occurrence of a substring in a string Signature: lastIndexOf(str, substring) Example:
Note: It can also be written as a transform when the first value is the input: value | lastIndexOf(...).

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length

Returns the length of a string or array Signature: length(strOrArr) Example:
Note: It can also be written as a transform when the first value is the input: value | length(...).

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reverse

Reverses a string or array Signature: reverse(val) Example:
Note: It can also be written as a transform when the first value is the input: value | reverse(...).

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toBoolean

Converts a string to a boolean. Accepts ‘true’ (case-insensitive) as true. Signature: toBoolean(val) Example:
Note: It can also be written as a transform when the first value is the input: value | toBoolean(...).

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toInt

Parses a value to an integer using optional radix Signature: toInt(value, radix?) Example:
Note: It can also be written as a transform when the first value is the input: value | toInt(...).

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toNumber

Converts a string to a number (or returns NaN if not possible) Signature: toNumber(val) Example:
Note: It can also be written as a transform when the first value is the input: value | toNumber(...).

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toStr

Converts any value to its string representation Signature: toStr(value) Example:
Note: It can also be written as a transform when the first value is the input: value | toStr(...).

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Before you publish

  • Start with a known value and confirm the expected result.
  • Handle null, empty text, and empty lists deliberately.
  • Do not place secrets, access tokens, or sensitive personal data in an expression.
  • Read expression contexts and availability before copying an expression between features.
Common conversion helpers in KayanOS