@algosail/string

String comparison, concatenation, and utility functions. All functions are curried. Operations on non-string inputs return safe defaults (false, '', []).

Contents

• equals
• lte / lt / gte / gt
• min / max / clamp
• concat
• empty
• toUpper / toLower / trim
• stripPrefix
• stripSuffix
• words / unwords
• lines / unlines
• splitOn
• splitOnRegex
• joinWith

equals

equals :: String -> String -> Boolean

True when both values are strings with identical content.

equals('hello')('hello') // => true
equals('hello')('world') // => false
equals('1')(1) // => false  — type matters

lte / lt / gte / gt

lte :: String -> String -> Boolean
lt  :: String -> String -> Boolean
gte :: String -> String -> Boolean
gt  :: String -> String -> Boolean

Lexicographic comparisons (native JS string ordering).

lte('a')('b') // => true
lte('b')('a') // => false
lte('abc')('abd') // => true

lt('a')('b') // => true
lt('b')('b') // => false

gte('b')('a') // => true
gt('b')('a') // => true

min / max / clamp

min   :: String -> String -> String
max   :: String -> String -> String
clamp :: String -> String -> String -> String

min('apple')('banana') // => 'apple'
max('apple')('banana') // => 'banana'

clamp('b')('d')('a') // => 'b'   (below lo)
clamp('b')('d')('c') // => 'c'   (in range)
clamp('b')('d')('e') // => 'd'   (above hi)

concat

concat :: String -> String -> String

Concatenates two strings. Returns '' if either argument is not a string.

concat('foo')('bar') // => 'foobar'
concat('hello')(' world') // => 'hello world'

empty

empty :: String

The empty string constant.

empty // => ''

toUpper / toLower / trim

toUpper :: String -> String
toLower :: String -> String
trim    :: String -> String

toUpper('hello') // => 'HELLO'
toLower('HELLO') // => 'hello'
trim('  hi  ') // => 'hi'
trim('\n text \t') // => 'text'

stripPrefix

stripPrefix :: String -> String -> Maybe String

Returns Just the remainder after stripping the prefix, or Nothing if the string does not start with the prefix.

stripPrefix('foo')('foobar') // => just('bar')
stripPrefix('foo')('foo') // => just('')
stripPrefix('foo')('bar') // => nothing()
stripPrefix('')('abc') // => just('abc')

stripSuffix

stripSuffix :: String -> String -> Maybe String

Returns Just the string with the suffix removed, or Nothing if it does not end with the suffix.

stripSuffix('bar')('foobar') // => just('foo')
stripSuffix('.js')('index.js') // => just('index')
stripSuffix('.ts')('index.js') // => nothing()

words / unwords

words   :: String -> Array String
unwords :: Array String -> String

Split on whitespace / join with a single space. Leading and trailing whitespace is ignored.

words('  foo bar  baz  ') // => ['foo', 'bar', 'baz']
words('') // => []
words('single') // => ['single']

unwords(['foo', 'bar', 'baz']) // => 'foo bar baz'
unwords([]) // => ''

lines / unlines

lines   :: String -> Array String
unlines :: Array String -> String

Split on \n, \r\n, or \r. unlines appends a terminating \n to each line.

lines('a\nb\nc') // => ['a', 'b', 'c']
lines('a\r\nb') // => ['a', 'b']
lines('') // => []

unlines(['a', 'b', 'c']) // => 'a\nb\nc\n'

splitOn

splitOn :: String -> String -> Array String

Splits a string on a separator substring.

splitOn(',')('a,b,c') // => ['a', 'b', 'c']
splitOn(', ')('a, b, c') // => ['a', 'b', 'c']
splitOn('::')('a::b::c') // => ['a', 'b', 'c']
splitOn(',')('no-separator') // => ['no-separator']

splitOnRegex

splitOnRegex :: RegExp -> String -> Array String

Splits on a regex pattern. The regex must have the g flag.

splitOnRegex(/\s+/g)('  foo  bar  baz  ') // => ['  ', 'foo', '  ', 'bar', '  ', 'baz', '  ']
splitOnRegex(/,\s*/g)('a, b,c , d') // => ['a', 'b', 'c', 'd']

joinWith

joinWith :: String -> Array String -> String

Joins an array of strings with the given separator.

joinWith('-')(['a', 'b', 'c']) // => 'a-b-c'
joinWith(', ')(['foo', 'bar']) // => 'foo, bar'
joinWith('')(['h', 'e', 'l', 'l', 'o']) // => 'hello'