Standard Library

Kite provides a rich standard library of built-in functions for common operations.

Output Functions

print(value)

Output a value without a newline.

print("Hello")
print(" World")
// Output: Hello World

println(value)

Output a value followed by a newline.

println("Hello")
println("World")
// Output:
// Hello
// World

Type Casting Functions

int(value)

Convert a value to an integer.

var x = int("42")      // 42
var y = int(3.7)       // 3
var z = int(true)      // Error: boolean can't be converted

number(value)

Convert a value to a number (floating-point).

var x = number("3.14")  // 3.14
var y = number(42)      // 42.0

decimal(value)

Convert a value to a decimal (high precision).

var price  = decimal("19.99")
var amount = decimal(100)

string(value)

Convert any value to its string representation.

var s = string(42)       // "42"
var t = string(true)     // "true"
var u = string([1,2,3])  // "[1, 2, 3]"

boolean(value)

Convert a value to a boolean.

var b = boolean(1)       // true
var c = boolean(0)       // false
var d = boolean("")      // false
var e = boolean("text")  // true

String Functions

length(value)

Get the length of a string or array.

var len  = length("Hello")   // 5
var size = length([1,2,3])  // 3

charAt(string, index)

Get the character at a specific index.

var ch   = charAt("Hello", 0)  // "H"
var last = charAt("Hello", 4)  // "o"

indexOf(string, search)

Find the index of a substring.

var pos      = indexOf("Hello World", "World")  // 6
var notFound = indexOf("Hello", "xyz")     // -1

substring(string, start, end?)

Extract a portion of a string.

var sub  = substring("Hello World", 0, 5)   // "Hello"
var rest = substring("Hello World", 6)     // "World"

toLowerCase(string)

Convert string to lowercase.

var lower = toLowerCase("HELLO") // "hello"

toUpperCase(string)

Convert string to uppercase.

var upper = toUpperCase("hello") // "HELLO"

trim(string)

Remove whitespace from both ends.

var cleaned = trim(" hello ") // "hello"

startsWith(string, prefix)

Check if string starts with prefix.

var result = startsWith("Hello World", "Hello") // true

endsWith(string, suffix)

Check if string ends with suffix.

var result = endsWith("file.txt", ".txt") // true

split(string, delimiter)

Split string into array.

var parts = split("a,b,c", ",") // ["a", "b", "c"]

replace(string, search, replacement)

Replace occurrences in string.

var result = replace("Hello World", "World", "Kite")
// "Hello Kite"

format(template, ...args)

Format string with arguments.

var msg = format("Hello, {0}! You have {1} messages.", "Alice", 5)
// "Hello, Alice! You have 5 messages."

Collection Functions

range(end) / range(start, end) / range(start, end, step)

Generate a range of numbers.

var r1 = range(5)         // [0, 1, 2, 3, 4]
var r2 = range(1, 5)      // [1, 2, 3, 4]
var r3 = range(0, 10, 2)  // [0, 2, 4, 6, 8]
var r4 = range(5, 0, -1)  // [5, 4, 3, 2, 1]

first(array)

Get the first element.

var f = first([1, 2, 3]) // 1

last(array)

Get the last element.

var l = last([1, 2, 3]) // 3

isEmpty(array)

Check if array is empty.

var empty    = isEmpty([])     // true
var notEmpty = isEmpty([1]) // false

contains(array, element)

Check if array contains element.

var has = contains([1, 2, 3], 2)  // true
var no  = contains([1, 2, 3], 5)   // false

push(array, element)

Add element to end of array (returns new array).

var newArr = push([1, 2], 3) // [1, 2, 3]

slice(array, start, end?)

Extract portion of array.

var part = slice([1, 2, 3, 4, 5], 1, 4)  // [2, 3, 4]
var rest = slice([1, 2, 3, 4, 5], 2)     // [3, 4, 5]

reverse(array)

Reverse array order.

var rev = reverse([1, 2, 3]) // [3, 2, 1]

sort(array)

Sort array in ascending order.

var sorted = sort([3, 1, 2])     // [1, 2, 3]
var names  = sort(["c", "a", "b"]) // ["a", "b", "c"]

distinct(array)

Remove duplicate elements.

var unique = distinct([1, 2, 2, 3, 1]) // [1, 2, 3]

flatten(array)

Flatten nested arrays.

var flat = flatten([[1, 2], [3, 4]]) // [1, 2, 3, 4]

join(array, separator)

Join array elements into string.

var str = join(["a", "b", "c"], "-") // "a-b-c"

sum(array)

Sum numeric array elements.

var total = sum([1, 2, 3, 4, 5]) // 15

average(array)

Calculate average of numeric array.

var avg = average([10, 20, 30]) // 20.0

find(array, predicate)

Find first element matching predicate.

var found = find([1, 2, 3, 4], (x) -> x > 2) // 3

zip(array1, array2)

Combine two arrays into pairs.

var pairs = zip([1, 2, 3], ["a", "b", "c"])
// [[1, "a"], [2, "b"], [3, "c"]]

Numeric Functions

abs(number)

Get absolute value.

var a = abs(-5)   // 5
var b = abs(5)    // 5

floor(number)

Round down to nearest integer.

var f = floor(3.7)   // 3
var g = floor(-3.2)  // -4

ceil(number)

Round up to nearest integer.

var c = ceil(3.2)   // 4
var d = ceil(-3.7)  // -3

round(number)

Round to nearest integer.

var r = round(3.5)  // 4
var s = round(3.4)  // 3

min(a, b)

Get minimum value.

var m = min(5, 3) // 3

max(a, b)

Get maximum value.

var m = max(5, 3) // 5

clamp(value, min, max)

Clamp value within range.

var c = clamp(15, 0, 10)  // 10
var d = clamp(-5, 0, 10)  // 0
var e = clamp(5, 0, 10)   // 5

pow(base, exponent)

Calculate power.

var p = pow(2, 3)   // 8
var q = pow(10, 2)  // 100

sqrt(number)

Calculate square root.

var s = sqrt(16)  // 4.0
var t = sqrt(2)   // 1.4142...

Object Functions

keys(object)

Get array of object keys.

var obj = { name: "Alice", age: 30 }
var k   = keys(obj)  // ["name", "age"]

values(object)

Get array of object values.

var obj = { name: "Alice", age: 30 }
var v   = values(obj)  // ["Alice", 30]

entries(object)

Get array of [key, value] pairs.

var obj = { a: 1, b: 2 }
var e   = entries(obj)  // [["a", 1], ["b", 2]]

hasKey(object, key)

Check if object has key.

var obj = { name: "Alice" }
var has = hasKey(obj, "name")   // true
var no  = hasKey(obj, "email")   // false

get(object, key, default?)

Get value with optional default.

var obj   = { name: "Alice" }
var name  = get(obj, "name")           // "Alice"
var age   = get(obj, "age", 0)          // 0 (default)
var email = get(obj, "email", null)   // null

merge(obj1, obj2, ...objN)

Merge multiple objects.

var a        = { x: 1 }
var b        = { y: 2 }
var c        = { z: 3 }
var merged   = merge(a, b, c)  // { x: 1, y: 2, z: 3 }
// Later objects override earlier ones
var override = merge({ a: 1 }, { a: 2 })  // { a: 2 }

Type Checking Functions

isString("hello")   // true
isNumber(42)        // true
isBoolean(true)     // true
isArray([1, 2, 3])  // true
isObject({ a: 1 })  // true
isNull(null)        // true

Date/Time Functions

now()

Get current date/time as ISO string.

var current = now() // "2024-01-15T10:30:00.000"

date(year, month, day)

Create a date.

var d = date(2024, 1, 15) // "2024-01-15"

timestamp()

Get current Unix timestamp (milliseconds).

var ts = timestamp() // e.g., 1705312200000

addDays(date, days)

Add days to date.

var later   = addDays("2024-01-15", 10)   // "2024-01-25"
var earlier = addDays("2024-01-15", -5)  // "2024-01-10"

diffDays(date1, date2)

Calculate difference in days between dates.

var diff = diffDays("2024-01-01", "2024-01-15") // 14

formatDate(date, pattern)

Format date using pattern.

var formatted = formatDate("2024-01-15", "MM/dd/yyyy")
// "01/15/2024"

Utility Functions

uuid()

Generate a random UUID.

var id = uuid() // "550e8400-e29b-41d4-a716-446655440000"

hash(value, algorithm?)

Calculate hash of a value. Default algorithm is SHA-256.

var h    = hash("hello")                    // SHA-256 hash
var md5  = hash("hello", "MD5")           // MD5 hash
var sha1 = hash("hello", "SHA-1")        // SHA-1 hash

base64Encode(string)

Encode string to Base64.

var encoded            = base64Encode("Hello, World!")
// "SGVsbG8sIFdvcmxkIQ =="

base64Decode(string)

Decode Base64 to string.

var decoded = base64Decode("SGVsbG8sIFdvcmxkIQ==")
// "Hello, World!"

toJson(value)

Convert value to JSON string.

var json = toJson({ name: "Alice", age: 30 })
// '{"name":"Alice","age":30}'

fromJson(string)

Parse JSON string to value.

var obj = fromJson('{"name":"Alice","age":30}')
// { name: "Alice", age: 30 }

env(name, default?)

Get environment variable.

var home = env("HOME")
var port = env("PORT", "8080")  // default if not set

Quick Reference

Category	Functions
Output	`print`, `println`
Cast	`int`, `number`, `decimal`, `string`, `boolean`, `any`
String	`length`, `charAt`, `indexOf`, `substring`, `toLowerCase`, `toUpperCase`, `trim`, `startsWith`, `endsWith`, `split`, `replace`, `format`
Collection	`range`, `first`, `last`, `isEmpty`, `contains`, `push`, `slice`, `reverse`, `sort`, `distinct`, `flatten`, `join`, `sum`, `average`, `find`, `zip`
Numeric	`abs`, `floor`, `ceil`, `round`, `min`, `max`, `clamp`, `pow`, `sqrt`
Object	`keys`, `values`, `entries`, `hasKey`, `get`, `merge`
Types	`isString`, `isNumber`, `isBoolean`, `isArray`, `isObject`, `isNull`
DateTime	`now`, `date`, `timestamp`, `addDays`, `diffDays`, `formatDate`
Utility	`uuid`, `hash`, `base64Encode`, `base64Decode`, `toJson`, `fromJson`, `env`

Explore more: Return to Syntax Basics or check the Documentation Home.