String2
Provide bindings to JS string. Optimized for pipe-first.
t
type t = stringmake
let make: 'a => tmake(value) converts the given value to a string.
Examples
RESCRIPTJs.String2.make(3.5) == "3.5"
Js.String2.make([1, 2, 3]) == "1,2,3"
fromCharCode
let fromCharCode: int => tfromCharCode(n) creates a string containing the character corresponding to
that number; n ranges from 0 to 65535.If out of range, the lower 16 bits of
the value are used. Thus, fromCharCode(0x1F63A) gives the same result as
fromCharCode(0xF63A).
See String.fromCharCode
on MDN.
Examples
RESCRIPTJs.String2.fromCharCode(65) == "A"
Js.String2.fromCharCode(0x3c8) == `ψ`
Js.String2.fromCharCode(0xd55c) == `한`
Js.String2.fromCharCode(-64568) == `ψ`
fromCharCodeMany
let fromCharCodeMany: array<int> => tfromCharCodeMany([n1, n2, n3]) creates a string from the characters
corresponding to the given numbers, using the same rules as fromCharCode.
See String.fromCharCode
on MDN.
fromCodePoint
let fromCodePoint: int => tfromCodePoint(n) creates a string containing the character corresponding to
that numeric code point. If the number is not a valid code point, it raises
RangeError. Thus, fromCodePoint(0x1F63A) will produce a correct value,
unlike fromCharCode(0x1F63A), and fromCodePoint(-5) will raise a
RangeError.
See String.fromCodePoint
on MDN.
Examples
RESCRIPTJs.String2.fromCodePoint(65) == "A"
Js.String2.fromCodePoint(0x3c8) == `ψ`
Js.String2.fromCodePoint(0xd55c) == `한`
Js.String2.fromCodePoint(0x1f63a) == `😺`
fromCodePointMany
let fromCodePointMany: array<int> => tfromCodePointMany([n1, n2, n3]) creates a string from the characters
corresponding to the given code point numbers, using the same rules as
fromCodePoint.
See String.fromCodePoint
on MDN.
Examples
RESCRIPTJs.String2.fromCodePointMany([0xd55c, 0xae00, 0x1f63a]) == `한글😺`
length
let length: t => intlength(s) returns the length of the given string.
See String.length
on MDN.
Examples
RESCRIPTJs.String2.length("abcd") == 4
get
let get: (t, int) => tget(s, n) returns as a string the character at the given index number. If
n is out of range, this function returns undefined,so at some point this
function may be modified to return option<string>.
Examples
RESCRIPTJs.String2.get("Reason", 0) == "R"
Js.String2.get("Reason", 4) == "o"
Js.String2.get(`Rẽasöń`, 5) == `ń`
charAt
let charAt: (t, int) => tcharAt(s, n) gets the character at index n within string s. If n is
negative or greater than the length of s, it returns the empty string. If the
string contains characters outside the range \u0000-\uffff, it will return the
first 16-bit value at that position in the string.
See String.charAt
on MDN.
Examples
RESCRIPTJs.String2.charAt("Reason", 0) == "R"
Js.String2.charAt("Reason", 12) == ""
Js.String2.charAt(`Rẽasöń`, 5) == `ń`
charCodeAt
let charCodeAt: (t, int) => floatcharCodeAt(s, n) returns the character code at position n in string s;
the result is in the range 0-65535, unlke codePointAt, so it will not work
correctly for characters with code points greater than or equal to 0x10000. The
return type is float because this function returns NaN if n is less than
zero or greater than the length of the string.
See String.charCodeAt
on MDN.
Examples
RESCRIPTJs.String2.charCodeAt(`😺`, 0) == 0xd83d->Belt.Int.toFloat
Js.String2.codePointAt(`😺`, 0) == Some(0x1f63a)
codePointAt
let codePointAt: (t, int) => option<int>codePointAt(s, n) returns the code point at position n within string s as
a Some(value). The return value handles code points greater than or equal to
0x10000. If there is no code point at the given position, the function returns
None.
See String.codePointAt
on MDN.
Examples
RESCRIPTJs.String2.codePointAt(`¿😺?`, 1) == Some(0x1f63a)
Js.String2.codePointAt("abc", 5) == None
concat
let concat: (t, t) => tconcat(original, append) returns a new string with append added after
original.
See String.concat
on MDN.
Examples
RESCRIPTJs.String2.concat("cow", "bell") == "cowbell"
concatMany
let concatMany: (t, array<t>) => tconcatMany(original, arr) returns a new string consisting of each item of an
array of strings added to the original string.
See String.concat
on MDN.
Examples
RESCRIPTJs.String2.concatMany("1st", ["2nd", "3rd", "4th"]) == "1st2nd3rd4th"
endsWith
let endsWith: (t, t) => boolES2015: endsWith(str, substr) returns true if the str ends with substr,
false otherwise.
See String.endsWith
on MDN.
Examples
RESCRIPTJs.String2.endsWith("ReScript", "Script") == true
Js.String2.endsWith("C++", "Script") == false
endsWithFrom
let endsWithFrom: (t, t, int) => boolendsWithFrom(str, ending, len) returns true if the first len characters of
str end with ending, false otherwise. If len is greater than or equal
to the length of str, then it works like endsWith. (Honestly, this should
have been named endsWithAt, but oh well).
See String.endsWith
on MDN.
Examples
RESCRIPTJs.String2.endsWithFrom("abcd", "cd", 4) == true
Js.String2.endsWithFrom("abcde", "cd", 3) == false
Js.String2.endsWithFrom("abcde", "cde", 99) == true
Js.String2.endsWithFrom("example.dat", "ple", 7) == true
includes
let includes: (t, t) => boolES2015: includes(str, searchValue) returns true if searchValue is found
anywhere within str, false otherwise.
See String.includes
on MDN.
Examples
RESCRIPTJs.String2.includes("programmer", "gram") == true
Js.String2.includes("programmer", "er") == true
Js.String2.includes("programmer", "pro") == true
Js.String2.includes("programmer.dat", "xyz") == false
includesFrom
let includesFrom: (t, t, int) => boolES2015: includes(str, searchValue start) returns true if searchValue is
found anywhere within str starting at character number start (where 0 is
the first character), false otherwise.
See String.includes
on MDN.
Examples
RESCRIPTJs.String2.includesFrom("programmer", "gram", 1) == true
Js.String2.includesFrom("programmer", "gram", 4) == false
Js.String2.includesFrom(`대한민국`, `한`, 1) == true
indexOf
let indexOf: (t, t) => intES2015: indexOf(str, searchValue) returns the position at which searchValue
was first found within str, or -1 if searchValue is not in str.
See String.indexOf
on MDN.
Examples
RESCRIPTJs.String2.indexOf("bookseller", "ok") == 2
Js.String2.indexOf("bookseller", "sell") == 4
Js.String2.indexOf("beekeeper", "ee") == 1
Js.String2.indexOf("bookseller", "xyz") == -1
indexOfFrom
let indexOfFrom: (t, t, int) => intindexOfFrom(str, searchValue, start) returns the position at which
searchValue was found within str starting at character position start, or
-1 if searchValue is not found in that portion of str. The return value is
relative to the beginning of the string, no matter where the search started
from.
See String.indexOf
on MDN.
Examples
RESCRIPTJs.String2.indexOfFrom("bookseller", "ok", 1) == 2
Js.String2.indexOfFrom("bookseller", "sell", 2) == 4
Js.String2.indexOfFrom("bookseller", "sell", 5) == -1
lastIndexOf
let lastIndexOf: (t, t) => intlastIndexOf(str, searchValue) returns the position of the last occurrence of
searchValue within str, searching backwards from the end of the string.
Returns -1 if searchValue is not in str. The return value is always
relative to the beginning of the string.
See String.lastIndexOf
on MDN.
Examples
RESCRIPTJs.String2.lastIndexOf("bookseller", "ok") == 2
Js.String2.lastIndexOf("beekeeper", "ee") == 4
Js.String2.lastIndexOf("abcdefg", "xyz") == -1
lastIndexOfFrom
let lastIndexOfFrom: (t, t, int) => intlastIndexOfFrom(str, searchValue, start) returns the position of the last
occurrence of searchValue within str, searching backwards from the given
start position. Returns -1 if searchValue is not in str. The return value
is always relative to the beginning of the string.
See String.lastIndexOf
on MDN.
Examples
RESCRIPTJs.String2.lastIndexOfFrom("bookseller", "ok", 6) == 2
Js.String2.lastIndexOfFrom("beekeeper", "ee", 8) == 4
Js.String2.lastIndexOfFrom("beekeeper", "ee", 3) == 1
Js.String2.lastIndexOfFrom("abcdefg", "xyz", 4) == -1
localeCompare
let localeCompare: (t, t) => floatlocaleCompare(reference, comparison) returns
a negative value if reference comes before comparison in sort order
zero if reference and comparison have the same sort order
a positive value if reference comes after comparison in sort order
See String.localeCompare on MDN.
Examples
RESCRIPTJs.String2.localeCompare("zebra", "ant") > 0.0
Js.String2.localeCompare("ant", "zebra") < 0.0
Js.String2.localeCompare("cat", "cat") == 0.0
Js.String2.localeCompare("CAT", "cat") > 0.0
match_
let match_: (t, Js_re.t) => option<array<option<t>>>match(str, regexp) matches a string against the given regexp. If there is
no match, it returns None. For regular expressions without the g modifier, if
there is a match, the return value is Some(array) where the array contains:
The entire matched string
Any capture groups if the regexp had parentheses For regular expressions with the g modifier, a matched expression returns
Some(array)with all the matched substrings and no capture groups.
See String.match
on MDN.
Examples
RESCRIPTJs.String2.match_("The better bats", %re("/b[aeiou]t/")) == Some(["bet"])
Js.String2.match_("The better bats", %re("/b[aeiou]t/g")) == Some(["bet", "bat"])
Js.String2.match_("Today is 2018-04-05.", %re("/(\d+)-(\d+)-(\d+)/")) ==
Some(["2018-04-05", "2018", "04", "05"])
Js.String2.match_("The large container.", %re("/b[aeiou]g/")) == None
normalize
let normalize: t => tnormalize(str) returns the normalized Unicode string using Normalization Form
Canonical (NFC) Composition. Consider the character ã, which can be represented
as the single codepoint \u00e3 or the combination of a lower case letter A
\u0061 and a combining tilde \u0303. Normalization ensures that both can be
stored in an equivalent binary representation.
See String.normalize
on MDN. See also Unicode technical report
#15 for details.
normalizeByForm
let normalizeByForm: (t, t) => tES2015: normalize(str, form) returns the normalized Unicode string using the
specified form of normalization, which may be one of:
"NFC" — Normalization Form Canonical Composition.
"NFD" — Normalization Form Canonical Decomposition.
"NFKC" — Normalization Form Compatibility Composition.
"NFKD" — Normalization Form Compatibility Decomposition.
See String.normalize on MDN.
See also Unicode technical report #15 for details.
repeat
let repeat: (t, int) => trepeat(str, n) returns a string that consists of n repetitions of str.
Raises RangeError if n is negative.
See String.repeat
on MDN.
Examples
RESCRIPTJs.String2.repeat("ha", 3) == "hahaha"
Js.String2.repeat("empty", 0) == ""
replace
let replace: (t, t, t) => tES2015: replace(str, substr, newSubstr) returns a new string which is
identical to str except with the first matching instance of substr replaced
by newSubstr. substr is treated as a verbatim string to match, not a
regular expression.
See String.replace
on MDN.
Examples
RESCRIPTJs.String2.replace("old string", "old", "new") == "new string"
Js.String2.replace("the cat and the dog", "the", "this") == "this cat and the dog"
replaceByRe
let replaceByRe: (t, Js_re.t, t) => treplaceByRe(str, regex, replacement) returns a new string where occurrences
matching regex have been replaced by replacement.
See String.replace
on MDN.
Examples
RESCRIPTJs.String2.replaceByRe("vowels be gone", %re("/[aeiou]/g"), "x") == "vxwxls bx gxnx"
Js.String2.replaceByRe("Juan Fulano", %re("/(\w+) (\w+)/"), "$2, $1") == "Fulano, Juan"
unsafeReplaceBy0
let unsafeReplaceBy0: (t, Js_re.t, (t, int, t) => t) => tReturns a new string with some or all matches of a pattern with no capturing
parentheses replaced by the value returned from the given function. The
function receives as its parameters the matched string, the offset at which the
match begins, and the whole string being matched.
See String.replace
on MDN.
Examples
RESCRIPTlet str = "beautiful vowels"
let re = %re("/[aeiou]/g")
let matchFn = (matchPart, _offset, _wholeString) => Js.String2.toUpperCase(matchPart)
Js.String2.unsafeReplaceBy0(str, re, matchFn) == "bEAUtIfUl vOwEls"
unsafeReplaceBy1
let unsafeReplaceBy1: (t, Js_re.t, (t, t, int, t) => t) => tReturns a new string with some or all matches of a pattern with one set of
capturing parentheses replaced by the value returned from the given function.
The function receives as its parameters the matched string, the captured
string, the offset at which the match begins, and the whole string being
matched.
See String.replace
on MDN.
Examples
RESCRIPTlet str = "Jony is 40"
let re = %re("/(Jony is )\d+/g")
let matchFn = (_match, part1, _offset, _wholeString) => {
part1 ++ "41"
}
Js.String2.unsafeReplaceBy1(str, re, matchFn) == "Jony is 41"
unsafeReplaceBy2
let unsafeReplaceBy2: (t, Js_re.t, (t, t, t, int, t) => t) => tReturns a new string with some or all matches of a pattern with two sets of
capturing parentheses replaced by the value returned from the given function.
The function receives as its parameters the matched string, the captured
strings, the offset at which the match begins, and the whole string being
matched.
See String.replace
on MDN.
Examples
RESCRIPTlet str = "7 times 6"
let re = %re("/(\d+) times (\d+)/")
let matchFn = (_match, p1, p2, _offset, _wholeString) => {
switch (Belt.Int.fromString(p1), Belt.Int.fromString(p2)) {
| (Some(x), Some(y)) => Belt.Int.toString(x * y)
| _ => "???"
}
}
Js.String2.unsafeReplaceBy2(str, re, matchFn) == "42"
unsafeReplaceBy3
let unsafeReplaceBy3: (t, Js_re.t, (t, t, t, t, int, t) => t) => tReturns a new string with some or all matches of a pattern with three sets of
capturing parentheses replaced by the value returned from the given function.
The function receives as its parameters the matched string, the captured
strings, the offset at which the match begins, and the whole string being
matched.
See String.replace
on MDN.
search
let search: (t, Js_re.t) => intsearch(str, regexp) returns the starting position of the first match of
regexp in the given str, or -1 if there is no match.
See String.search
on MDN.
Examples
RESCRIPTJs.String2.search("testing 1 2 3", %re("/\d+/")) == 8
Js.String2.search("no numbers", %re("/\d+/")) == -1
slice
let slice: (t, ~from: int, ~to_: int) => tslice(str, from:n1, to_:n2) returns the substring of str starting at
character n1 up to but not including n2.
If either
n1orn2is negative, then it is evaluated aslength(str - n1)orlength(str - n2).If
n2is greater than the length ofstr, then it is treated aslength(str).If
n1is greater thann2, slice returns the empty string.
See String.slice on MDN.
Examples
RESCRIPTJs.String2.slice("abcdefg", ~from=2, ~to_=5) == "cde"
Js.String2.slice("abcdefg", ~from=2, ~to_=9) == "cdefg"
Js.String2.slice("abcdefg", ~from=-4, ~to_=-2) == "de"
Js.String2.slice("abcdefg", ~from=5, ~to_=1) == ""
sliceToEnd
let sliceToEnd: (t, ~from: int) => tsliceToEnd(str, from:n) returns the substring of str starting at character
n to the end of the string.
If
nis negative, then it is evaluated aslength(str - n).If
nis greater than the length ofstr, then sliceToEnd returns the empty string.
See String.slice on MDN.
Examples
RESCRIPTJs.String2.sliceToEnd("abcdefg", ~from=4) == "efg"
Js.String2.sliceToEnd("abcdefg", ~from=-2) == "fg"
Js.String2.sliceToEnd("abcdefg", ~from=7) == ""
split
let split: (t, t) => array<t>split(str, delimiter) splits the given str at every occurrence of
delimiter and returns an array of the resulting substrings.
See String.split
on MDN.
Examples
RESCRIPTJs.String2.split("2018-01-02", "-") == ["2018", "01", "02"]
Js.String2.split("a,b,,c", ",") == ["a", "b", "", "c"]
Js.String2.split("good::bad as great::awful", "::") == ["good", "bad as great", "awful"]
Js.String2.split("has-no-delimiter", ";") == ["has-no-delimiter"]
splitAtMost
let splitAtMost: (t, t, ~limit: int) => array<t>splitAtMost delimiter ~limit: n str splits the given str at every occurrence of delimiter and returns an array of the first n resulting substrings. If n is negative or greater than the number of substrings, the array will contain all the substrings.
splitAtMost "ant/bee/cat/dog/elk" "/" ~limit: 3 = [|"ant"; "bee"; "cat"|];; splitAtMost "ant/bee/cat/dog/elk" "/" ~limit: 0 = [| |];; splitAtMost "ant/bee/cat/dog/elk" "/" ~limit: 9 = [|"ant"; "bee"; "cat"; "dog"; "elk"|];;
splitByRe
let splitByRe: (t, Js_re.t) => array<option<t>>splitByRe(str, regex) splits the given str at every occurrence of regex
and returns an array of the resulting substrings.
See String.split
on MDN.
Examples
RESCRIPTJs.String2.splitByRe("art; bed , cog ;dad", %re("/\s*[,;]\s*TODO/")) == [
Some("art"),
Some("bed"),
Some("cog"),
Some("dad"),
]
splitByReAtMost
let splitByReAtMost: (t, Js_re.t, ~limit: int) => array<option<t>>splitByReAtMost(str, regex, ~limit:n) splits the given str at every
occurrence of regex and returns an array of the first n resulting
substrings. If n is negative or greater than the number of substrings, the
array will contain all the substrings.
See String.split
on MDN.
Examples
RESCRIPTJs.String2.splitByReAtMost("one: two: three: four", %re("/\s*:\s*TODO/"), ~limit=3) == [
Some("one"),
Some("two"),
Some("three"),
]
Js.String2.splitByReAtMost("one: two: three: four", %re("/\s*:\s*TODO/"), ~limit=0) == []
Js.String2.splitByReAtMost("one: two: three: four", %re("/\s*:\s*TODO/"), ~limit=8) == [
Some("one"),
Some("two"),
Some("three"),
Some("four"),
]
startsWith
let startsWith: (t, t) => boolES2015: startsWith(str, substr) returns true if the str starts with
substr, false otherwise.
See String.startsWith
on MDN.
Examples
RESCRIPTJs.String2.startsWith("ReScript", "Re") == true
Js.String2.startsWith("ReScript", "") == true
Js.String2.startsWith("JavaScript", "Re") == false
startsWithFrom
let startsWithFrom: (t, t, int) => boolES2015: startsWithFrom(str, substr, n) returns true if the str starts
with substr starting at position n, false otherwise. If n is negative,
the search starts at the beginning of str.
See String.startsWith
on MDN.
Examples
RESCRIPTJs.String2.startsWithFrom("ReScript", "Scri", 2) == true
Js.String2.startsWithFrom("ReScript", "", 2) == true
Js.String2.startsWithFrom("JavaScript", "Scri", 2) == false
substr
let substr: (t, ~from: int) => tsubstr(str, ~from:n) returns the substring of str from position n to the
end of the string.
If
nis less than zero, the starting position is the length ofstr - n.If
nis greater than or equal to the length ofstr, returns the empty string.
JavaScript’s String.substr() is a legacy function. When possible, use
substring() instead.
See String.substr
on MDN.
Examples
RESCRIPTJs.String2.substr("abcdefghij", ~from=3) == "defghij"
Js.String2.substr("abcdefghij", ~from=-3) == "hij"
Js.String2.substr("abcdefghij", ~from=12) == ""
substrAtMost
let substrAtMost: (t, ~from: int, ~length: int) => tsubstrAtMost(str, ~from: pos, ~length: n) returns the substring of str of
length n starting at position pos.
If
posis less than zero, the starting position is the length ofstr - pos.If
posis greater than or equal to the length ofstr, returns the empty string.If
nis less than or equal to zero, returns the empty string.
JavaScript’s String.substr() is a legacy function. When possible, use
substring() instead.
See String.substr
on MDN.
Examples
RESCRIPTJs.String2.substrAtMost("abcdefghij", ~from=3, ~length=4) == "defg"
Js.String2.substrAtMost("abcdefghij", ~from=-3, ~length=4) == "hij"
Js.String2.substrAtMost("abcdefghij", ~from=12, ~length=2) == ""
substring
let substring: (t, ~from: int, ~to_: int) => tsubstring(str, ~from: start, ~to_: finish) returns characters start up to
but not including finish from str.
If
startis less than zero, it is treated as zero.If
finishis zero or negative, the empty string is returned.If
startis greater thanfinish, thestartandfinishpoints are swapped.
See String.substring on MDN.
Examples
RESCRIPTJs.String2.substring("playground", ~from=3, ~to_=6) == "ygr"
Js.String2.substring("playground", ~from=6, ~to_=3) == "ygr"
Js.String2.substring("playground", ~from=4, ~to_=12) == "ground"
substringToEnd
let substringToEnd: (t, ~from: int) => tsubstringToEnd(str, ~from: start) returns the substring of str from
position start to the end.
If
startis less than or equal to zero, the entire string is returned.If
startis greater than or equal to the length ofstr, the empty string is returned.
See String.substring on MDN.
Examples
RESCRIPTJs.String2.substringToEnd("playground", ~from=4) == "ground"
Js.String2.substringToEnd("playground", ~from=-3) == "playground"
Js.String2.substringToEnd("playground", ~from=12) == ""
toLowerCase
let toLowerCase: t => ttoLowerCase(str) converts str to lower case using the locale-insensitive
case mappings in the Unicode Character Database. Notice that the conversion can
give different results depending upon context, for example with the Greek
letter sigma, which has two different lower case forms; one when it is the last
character in a string and another when it is not.
See String.toLowerCase
on MDN.
Examples
RESCRIPTJs.String2.toLowerCase("ABC") == "abc"
Js.String2.toLowerCase(`ΣΠ`) == `σπ`
Js.String2.toLowerCase(`ΠΣ`) == `πς`
toLocaleLowerCase
let toLocaleLowerCase: t => ttoLocaleLowerCase(str) converts str to lower case using the current locale.
See String.toLocaleLowerCase
on MDN.
toUpperCase
let toUpperCase: t => ttoUpperCase(str) converts str to upper case using the locale-insensitive
case mappings in the Unicode Character Database. Notice that the conversion can
expand the number of letters in the result; for example the German ß
capitalizes to two Ses in a row.
See String.toUpperCase
on MDN.
Examples
RESCRIPTJs.String2.toUpperCase("abc") == "ABC"
Js.String2.toUpperCase(`Straße`) == `STRASSE`
Js.String2.toUpperCase(`πς`) == `ΠΣ`
toLocaleUpperCase
let toLocaleUpperCase: t => ttoLocaleUpperCase(str) converts str to upper case using the current locale.
See String.to:LocaleUpperCase
on MDN.
trim
let trim: t => ttrim(str) returns a string that is str with whitespace stripped from both
ends. Internal whitespace is not removed.
See String.trim
on MDN.
Examples
RESCRIPTJs.String2.trim(" abc def ") == "abc def"
Js.String2.trim("\n\r\t abc def \n\n\t\r ") == "abc def"
anchor
let anchor: (t, t) => tanchor(anchorText, anchorName) creates a string with an HTML <a> element
with name attribute of anchorName and anchorText as its content. Please do
not use this method, as it has been removed from the relevant web standards.
See String.anchor
on MDN.
Examples
RESCRIPTJs.String2.anchor("Page One", "page1") == "<a name="page1">Page One</a>"
link
let link: (t, t) => tES2015: link(linkText, urlText) creates a string with an HTML <a> element
with href attribute of urlText and linkText as its content. Please do not
use this method, as it has been removed from the relevant web standards. See
String.link
on MDN.
Examples
RESCRIPTJs.String2.link("Go to page two", "page2.html") == "<a href="page2.html">Go to page two</a>"
castToArrayLike
let castToArrayLike: t => Js_array2.array_like<t>