Standard Library Overview

Tova provides 220+ built-in functions that are automatically available in every Tova program. There is nothing to import -- all standard library functions are in scope by default.

Availability

Standard library functions work everywhere Tova code runs:

• tova run -- all functions available in scripts and the REPL
• Server code -- all functions available in route handlers and server modules
• Client code -- functions are tree-shaken so only the ones you actually use are included in the browser bundle

Design Philosophy

Tova's standard library follows a few guiding principles:

• Functional style -- most functions take data as the first argument and return new values rather than mutating
• Result and Option types -- instead of throw and try/catch, Tova uses Ok/Err and Some/None for principled error handling
• Pipeable -- every function works naturally with the pipe operator |>
• Method syntax -- many functions (especially string functions) can be called as methods: "hello".upper() is the same as upper("hello")

Categories at a Glance

Category	Functions	Page
Collections	len, range, filled, enumerate, sum, sorted, reversed, zip, min, max, typeOf, filter, map, find, findIndex, includes, any, all, flatMap, reduce, unique, groupBy, chunk, flatten, take, drop, first, last, count, partition, print, zipWith, frequencies, scan, minBy, maxBy, sumBy, product, slidingWindow, intersection, difference, symmetricDifference, isSubset, isSuperset, union, pairwise, combinations, permutations, intersperse, interleave, repeatValue, binarySearch, isSorted, compact, rotate, insertAt, removeAt, updateAt, parallelMap	Collections
Strings	trim, trimStart, trimEnd, split, join, replace, replaceFirst, repeat, upper, lower, contains, startsWith, endsWith, chars, words, lines, charAt, padStart, padEnd, capitalize, titleCase, snakeCase, camelCase, kebabCase, indexOf, lastIndexOf, countOf, substr, reverseStr, center, isEmpty, truncate, wordWrap, dedent, indentStr, slugify, escapeHtml, unescapeHtml, fmt	Strings
Math & Stats	PI, E, INF, abs, floor, ceil, round, trunc, sign, clamp, sqrt, pow, sin, cos, tan, asin, acos, atan, atan2, ln, log2, log10, exp, isNaN, isFinite, isClose, toRadians, toDegrees, gcd, lcm, factorial, random, randomInt, randomFloat, choice, sample, shuffle, sleep, hypot, lerp, divmod, avg, mean, median, mode, stdev, variance, percentile, formatNumber, toHex, toBinary, toOctal, toFixed, typedSum, typedDot, typedNorm, typedAdd, typedScale, typedMap, typedReduce, typedSort, typedZeros, typedOnes, typedFill, typedRange, typedLinspace	Math & Stats
Objects & Utilities	keys, values, entries, merge, freeze, clone, hasKey, get, fromEntries, pick, omit, mapValues	Objects & Utilities
Functional	compose, pipeFn, identity, memoize, debounce, throttle, once, negate, partial, curry, flip	Functional
Regex	regexTest, regexMatch, regexFindAll, regexReplace, regexSplit, regexCapture, regexBuilder	Regex
Validation	isEmail, isUrl, isNumeric, isAlpha, isAlphanumeric, isUuid, isHex	Validation
URL & UUID	uuid, parseUrl, buildUrl, parseQuery, buildQuery	URL & UUID
HTTP Client	http.get, http.post, http.put, http.patch, http.delete, http.head, http.get_stream	HTTP Client
Date & Time	now, nowIso, dateParse, dateFormat, dateAdd, dateDiff, dateFrom, datePart, timeAgo	Date & Time
JSON	jsonParse, jsonStringify, jsonPretty	JSON
Encoding	base64Encode, base64Decode, urlEncode, urlDecode, hexEncode, hexDecode	Encoding
Async & Error Handling	tryFn, tryAsync, parallel, race, timeout, retry, sleep	Async & Error Handling
Result & Option	Ok, Err, Some, None, ? (propagation), filterOk, filterErr	Result & Option
Type Conversion	toInt, toFloat, toString, toBool	Type Conversion
Assertions	assert, assertEq, assertNe, assertThrows, assertSnapshot	Assertions
Lazy Iterators	iter, Seq.filter, Seq.map, Seq.take, Seq.drop, Seq.zip, Seq.flatMap, Seq.enumerate, Seq.collect, Seq.reduce, Seq.first, Seq.count, Seq.forEach, Seq.any, Seq.all, Seq.find	Lazy Iterators
Advanced Collections	OrderedDict, DefaultDict, Counter, Deque	Advanced Collections
Channels	Channel.new, ch.send, ch.receive, ch.close	Channels
Terminal & CLI	color, green, red, yellow, blue, cyan, magenta, gray, bold, dim, underline, strikethrough, table, panel, progress, spin, ask, confirm, choose, chooseMany, secret	Terminal & CLI
Scripting I/O	read, write, fs.exists, fs.readText, fs.writeText, fs.ls, fs.mkdir, fs.rm, fs.globFiles, sh, exec, spawn, env, args, parseArgs, exit, pathJoin, pathBasename, pathDirname	Scripting I/O
Tables	Table, where, select, derive, sortBy, groupBy, agg, window, join, pivot, unpivot, explode, peek, describe	Tables
Charting	barChart, lineChart, scatterChart, histogram, pieChart, heatmap	Charting
Sampling	sample, stratified_sample	Sampling
Database	sqlite, db.query, db.exec, db.writeTable, db.close	Database
Testing	Gen.int, Gen.float, Gen.bool, Gen.string, Gen.array, Gen.oneOf, forAll, createSpy, createMock	Testing

Quick Reference

I/O

print("Hello, World!")
print("Name:", name, "Age:", age)

Collections

len([1, 2, 3])                  // 3
range(5)                         // [0, 1, 2, 3, 4]
sorted([3, 1, 2])               // [1, 2, 3]
zip([1, 2], ["a", "b"])         // [[1, "a"], [2, "b"]]
unique([1, 2, 2, 3])            // [1, 2, 3]

Strings

upper("hello")                   // "HELLO"
split("a,b,c", ",")             // ["a", "b", "c"]
"hello".contains("ell")         // true

Math

abs(-5)                          // 5
clamp(15, 0, 10)                // 10
sqrt(16)                         // 4

Objects

keys({ a: 1, b: 2 })           // ["a", "b"]
merge({ a: 1 }, { b: 2 })      // { a: 1, b: 2 }
get(user, "address.city")       // safe nested access
pick(obj, ["name", "email"])    // select keys

Functional

double_then_inc = compose(fn(x) x + 1, fn(x) x * 2)
cached = memoize(expensive_fn)
run_once = once(fn() init_app())

JSON & Encoding

jsonParse('{"a": 1}')          // Ok({ a: 1 })
jsonPretty({ a: 1 })           // formatted JSON string
base64Encode("hello")          // "aGVsbG8="
urlEncode("hello world")       // "hello%20world"

Regex

regexTest("hello123", "\\d+")         // true
regexReplace("a1b2c3", "\\d", "X")   // "aXbXcX"
regexFindAll("a1b2c3", "\\d")        // [{match: "1"}, ...]

Validation

isEmail("user@example.com")           // true
isUrl("https://tova.dev")            // true
isUuid("550e8400-e29b-41d4-a716-446655440000")  // true

URL & UUID

id = uuid()                             // "a1b2c3d4-..."
parseQuery("a=1&b=2")                 // { a: "1", b: "2" }
buildUrl({ host: "api.com", pathname: "/v1" })

HTTP Client

// GET request
var result = http.get("https://api.example.com/users")
data = result.unwrap().body

// POST with JSON body
result = http.post("https://api.example.com/users", { name: "Alice" })

// With query params and bearer auth
result = http.get("https://api.example.com/search", {
  params: { q: "tova", limit: 10 },
  bearer: env("API_TOKEN")
})

Date & Time

d = dateParse("2024-01-15")           // Ok(Date)
dateFormat(d.unwrap(), "YYYY-MM-DD")  // "2024-01-15"
dateAdd(d.unwrap(), 7, "days")        // Date (7 days later)
timeAgo(d.unwrap())                    // "3 months ago"

Async & Error Handling

async fn main() {
  result = tryFn(fn() risky_operation())
  var data = await parallel([fetch("/a"), fetch("/b")])
  data = await retry(fn() fetch("/api"), { times: 3 })
}

main()

Result & Option

result = Ok(42)
result.map(fn(x) x * 2)        // Ok(84)
result.unwrap()                  // 42

option = Some("hello")
option.unwrapOr("default")      // "hello"
None.unwrapOr("default")        // "default"

Terminal & CLI

async fn main() {
  print("{green("Success: ")}{bold("All tests passed")}")
  print(table(data, { headers: ["Name", "Score"] }))
  name = await ask("What is your name?")
  ok = await confirm("Deploy to production?")
}

main()

Assertions

assert(len(items) > 0, "items must not be empty")
assertEq(add(2, 3), 5)

Using with Pipes

All standard library functions are designed to work with the pipe operator |>:

[1, 2, 3, 4, 5]
  |> filter(fn(x) x > 2)
  |> map(fn(x) x * 10)
  |> sum()
// 120

"Hello, World"
  |> lower()
  |> split(", ")
  |> first()
// "hello"

Migration to camelCase

As of v0.9.16, Tova's standard library uses camelCase naming for all multi-word functions. The old snake_case names still work but emit a deprecation warning:

// Old (deprecated — produces a warning):
var x = group_by(users, fn(u) u.city)

// New (preferred):
x = groupBy(users, fn(u) u.city)

The compiler will display a warning with a hint showing the new name:

warning: [W_DEPRECATED_STDLIB] 'group_by' is deprecated, use 'groupBy' instead
    --> app.tova:5:5
    |
  5 | x = group_by(users, fn(u) u.city)
    |     ^^^^^^^^
    = hint: rename to groupBy

In your IDE, deprecated names will appear with a strikethrough in autocomplete.

Common renames

Old name	New name
type_of	typeOf
flat_map	flatMap
group_by	groupBy
sort_by	sortBy
find_index	findIndex
starts_with	startsWith
ends_with	endsWith
json_parse	jsonParse
assert_eq	assertEq
to_int	toInt
to_string	toString
is_empty	isEmpty
table_where	tableWhere
bar_chart	barChart

All ~170 snake_case functions have camelCase equivalents. The pattern is consistent: snake_case → camelCase (e.g., read_text → readText, parallel_map → parallelMap).