String

String data type is used to represent textual data — such as sequences of characters or words. Strings can be defined by enclosing the text in either single quotes (‘) or double quotes (“).

Template strings use backticks and support interpolation with ${}.

The following examples are all valid:

"valid string double quote";
'valid string single quote';
`valid string with interpolation ${customer.firstName}`;

String Slicing

You can extract a substring using slice notation [start:end], where the character at the start index is included and the character at the end index is excluded.

"hello"[1:3]    // "el"
"hello"[0:2]    // "he"

Operators

Concatenation: a + b Equality: a == b Inequality: a != b

Functions

len

Returns the total number of characters it contains.

len('hello'); // 5

upper

Converts a given string to its uppercase form.

upper('hello'); // "HELLO"

lower

Converts a given string to its lowercase form.

lower('HeLLo'); // "hello"

trim

Removes leading and trailing whitespace from a string.

trim('  hello  '); // "hello"

startsWith

Takes two inputs and returns true if the first string begins with the second value.

startsWith('Hello John', 'Hello');  // true
startsWith('Hello John', 'Doe');    // false

endsWith

Returns true if the first string ends with the second value provided.

endsWith('Hello John', 'John');     // true
endsWith('Hello John', 'Hello');    // false

contains

Checks whether the first string includes the second value and returns true if it does.

contains('Hello John', 'ello');     // true
contains('Hello John', 'John');     // true
contains('Hello John', 'Doe');      // false

matches

Evaluates whether the input string satisfies a given regular expression pattern and returns true if it matches.

matches('12345', '^\d+$');   // true
matches('1234a', '^\d+$');   // false

extract

Uses a regular expression to return an array containing the captured groups from the input string.

extract('2025-06-01', '(\d{4})-(\d{2})-(\d{2})'); // ["2025-06-01", "2025", "06", "01"]
extract('foo.bar', '(\w+)\.(\w+)');                // ["foo.bar", "foo", "bar"]

split

Splits a string into an array of substrings using a delimiter.

split('a,b,c', ',');         // ["a", "b", "c"]
split('hello world', ' ');   // ["hello", "world"]

fuzzyMatch

Performs a fuzzy (approximate) string comparison between two strings. Returns a score between 0 and 1, where 1 is an exact match.

fuzzyMatch('hello', 'helo');     // 0.8 (approximate)
fuzzyMatch('apple', 'orange');   // low score

string

Convert the input into a string format; throws an error if the conversion fails.

string(20);     // "20"
string(true);   // "true"

Expression Syntax

Number