The stable release documentation can be found here https://epeli.github.io/underscore.string/

Underscore.string

Javascript lacks complete string manipulation operations. This is an attempt to fill that gap. List of build-in methods can be found for example from Dive Into JavaScript. Originally started as an Underscore.js extension but is a full standalone library nowadays.

Upgrading from 2.x to 3.x? Please read the changelog.

Usage

For Node.js, Browserify and Webpack

Install from npm

npm install underscore.string

Require individual functions

1var slugify = require("underscore.string/slugify");
2
3slugify("Hello world!");
4// => hello-world

or load the full library to enable chaining

1var s = require("underscore.string");
2
3s("   epeli  ").trim().capitalize().value();
4// => "Epeli"

but especially when using with Browserify the individual function approach is recommended because using it you only add those functions to your bundle you use.

In Meteor

From your Meteor project folder

1    meteor add underscorestring:underscore.string

and you'll be able to access the library with the s global from both the server and the client.

1s.slugify("Hello world!");
2// => hello-world
3
4s("   epeli  ").trim().capitalize().value();
5// => "Epeli"

Others

The dist/underscore.string.js file is an UMD build. You can load it using an AMD loader such as RequireJS or just stick it to a web page and access the library from the s global.

Underscore.js/Lo-Dash integration

It is still possible use as Underscore.js/Lo-Dash extension

1_.mixin(s.exports());

But it's not recommended since include, contains, reverse and join are dropped because they collide with the functions already defined by Underscore.js.

Lo-Dash-FP/Ramda integration

If you want to use underscore.string with ramdajs or Lo-Dash-FP you can use underscore.string.fp.

npm install underscore.string.fp

1var S = require('underscore.string.fp');
2var filter = require('lodash-fp').filter;
3var filter = require('ramda').filter;
4
5filter(S.startsWith('.'), [
6  '.vimrc',
7  'foo.md',
8  '.zshrc'
9]);
10// => ['.vimrc', '.zshrc']

Download

• Development version Uncompressed with Comments
• Production version Minified

API

Individual functions

numberFormat(number, [ decimals=0, decimalSeparator='.', orderSeparator=',']) => string

Formats the numbers.

1numberFormat(1000, 2);
2// => "1,000.00"
3
4numberFormat(123456789.123, 5, ".", ",");
5// => "123,456,789.12300"

levenshtein(string1, string2) => number

Calculates [Levenshtein distance][ld] between two strings. [ld]: http://en.wikipedia.org/wiki/Levenshtein_distance

1levenshtein("kitten", "kittah");
2// => 2

capitalize(string, [lowercaseRest=false]) => string

Converts first letter of the string to uppercase. If true is passed as second argument the rest of the string will be converted to lower case.

1capitalize("foo Bar");
2// => "Foo Bar"
3
4capitalize("FOO Bar", true);
5// => "Foo bar"

decapitalize(string) => string

Converts first letter of the string to lowercase.

1decapitalize("Foo Bar");
2// => "foo Bar"

chop(string, step) => array

1chop("whitespace", 3);
2// => ["whi", "tes", "pac", "e"]

clean(string) => string

Trim and replace multiple spaces with a single space.

1clean(" foo    bar   ");
2// => "foo bar"

cleanDiacritics(string) => string

Replace diacritic characters with closest ASCII equivalents. Check the source for supported characters. Pull requests welcome for missing characters!

1cleanDiacritics("ääkkönen");
2// => "aakkonen"

chars(string) => array

1chars("Hello");
2// => ["H", "e", "l", "l", "o"]

swapCase(string) => string

Returns a copy of the string in which all the case-based characters have had their case swapped.

1swapCase("hELLO");
2// => "Hello"

include(string, substring) => boolean

Tests if string contains a substring.

1include("foobar", "ob");
2// => true

count(string, substring) => number

Returns number of occurrences of substring in string.

1count("Hello world", "l");
2// => 3

escapeHTML(string) => string

Converts HTML special characters to their entity equivalents. This function supports cent, yen, euro, pound, lt, gt, copy, reg, quote, amp, apos.

1escapeHTML("<div>Blah blah blah</div>");
2// => "&lt;div&gt;Blah blah blah&lt;/div&gt;"

unescapeHTML(string) => string

Converts entity characters to HTML equivalents. This function supports cent, yen, euro, pound, lt, gt, copy, reg, quote, amp, apos, nbsp.

1unescapeHTML("<div>Blah blah blah</div>");
2// => "<div>Blah blah blah</div>"

insert(string, index, substring) => string

1insert("Hellworld", 4, "o ");
2// => "Hello world"

replaceAll(string, find, replace, [ignorecase=false]) => string

1replaceAll("foo", "o", "a");
2// => "faa"

isBlank(string) => boolean

1isBlank(""); // => true
2isBlank("\n"); // => true
3isBlank(" "); // => true
4isBlank("a"); // => false

join(separator, ...strings) => string

Joins strings together with given separator

1join(" ", "foo", "bar");
2// => "foo bar"

lines(str) => array

Split lines to an array

1lines("Hello\nWorld");
2// => ["Hello", "World"]

wrap(str, options) => string

Splits a line str (default '') into several lines of size options.width (default 75) using a options.seperator (default '\n'). If options.trailingSpaces is true, make each line at least width long using trailing spaces. If options.cut is true, create new lines in the middle of words. If options.preserveSpaces is true, preserve the space that should be there at the end of a line (only works if options.cut is false).

1wrap("Hello World", { width:5 })
2// => "Hello\nWorld"
3
4wrap("Hello World", { width:6, seperator:'.', trailingSpaces: true })
5// => "Hello .World "
6
7wrap("Hello World", { width:5, seperator:'.', cut:true, trailingSpaces: true })
8// => "Hello. Worl.d    "
9
10wrap("Hello World", { width:5, seperator:'.', preserveSpaces: true })
11// => "Hello .World"
12

dedent(str, [pattern]) => string

Dedent unnecessary indentation or dedent by a pattern.

Credits go to @sindresorhus. This implementation is similar to https://github.com/sindresorhus/strip-indent

1dedent("  Hello\n    World");
2// => "Hello\n  World"
3
4dedent("\t\tHello\n\t\t\t\tWorld");
5// => "Hello\n\t\tWorld"
6
7dedent("    Hello\n    World", "  "); // Dedent by 2 spaces
8// => "  Hello\n  World"

reverse(string) => string

Return reversed string:

1reverse("foobar");
2// => "raboof"

splice(string, index, howmany, substring) => string

Like an array splice.

1splice("https://edtsech@bitbucket.org/edtsech/underscore.strings", 30, 7, "epeli");
2// => "https://edtsech@bitbucket.org/epeli/underscore.strings"

startsWith(string, starts, [position]) => boolean

This method checks whether the string begins with starts at position (default: 0).

1startsWith("image.gif", "image");
2// => true
3
4startsWith(".vimrc", "vim", 1);
5// => true

endsWith(string, ends, [position]) => boolean

This method checks whether the string ends with ends at position (default: string.length).

1endsWith("image.gif", "gif");
2// => true
3
4endsWith("image.old.gif", "old", 9);
5// => true

pred(string) => string

Returns the predecessor to str.

1pred("b");
2// => "a"
3
4pred("B");
5// => "A"

succ(string) => string

Returns the successor to str.

1succ("a");
2// => "b"
3
4succ("A");
5// => "B"

titleize(string) => string

1titleize("my name is epeli");
2// => "My Name Is Epeli"

camelize(string, [decapitalize=false]) => string

Converts underscored or dasherized string to a camelized one. Begins with a lower case letter unless it starts with an underscore, dash or an upper case letter.

1camelize("moz-transform");
2// => "mozTransform"
3
4camelize("-moz-transform");
5// => "MozTransform"
6
7camelize("_moz_transform");
8// => "MozTransform"
9
10camelize("Moz-transform");
11// => "MozTransform"
12
13camelize("-moz-transform", true);
14// => "mozTransform"

classify(string) => string

Converts string to camelized class name. First letter is always upper case

1classify("some_class_name");
2// => "SomeClassName"

underscored(string) => string

Converts a camelized or dasherized string into an underscored one

1underscored("MozTransform");
2// => "moz_transform"

dasherize(string) => string

Converts a underscored or camelized string into an dasherized one

1dasherize("MozTransform");
2// => "-moz-transform"

humanize(string) => string

Converts an underscored, camelized, or dasherized string into a humanized one. Also removes beginning and ending whitespace, and removes the postfix '_id'.

1humanize("  capitalize dash-CamelCase_underscore trim  ");
2// => "Capitalize dash camel case underscore trim"

trim(string, [characters]) => string

Trims defined characters from begining and ending of the string. Defaults to whitespace characters.

1trim("  foobar   ");
2// => "foobar"
3
4trim("_-foobar-_", "_-");
5// => "foobar"

ltrim(string, [characters]) => string

Left trim. Similar to trim, but only for left side.

rtrim(string, [characters]) => string

Right trim. Similar to trim, but only for right side.

truncate(string, length, [truncateString = '...']) => string

1truncate("Hello world", 5);
2// => "Hello..."
3
4truncate("Hello", 10);
5// => "Hello"

prune(string, length, pruneString) => string

Elegant version of truncate. Makes sure the pruned string does not exceed the original length. Avoid half-chopped words when truncating.

1prune("Hello, world", 5);
2// => "Hello..."
3
4prune("Hello, world", 8);
5// => "Hello..."
6
7prune("Hello, world", 5, " (read a lot more)");
8// => "Hello, world" (as adding "(read a lot more)" would be longer than the original string)
9
10prune("Hello, cruel world", 15);
11// => "Hello, cruel..."
12
13prune("Hello", 10);
14// => "Hello"

words(str, delimiter=/\s+/) => array

Split string by delimiter (String or RegExp), /\s+/ by default.

1words("   I   love   you   ");
2// => ["I", "love", "you"]
3
4words("I_love_you", "_");
5// => ["I", "love", "you"]
6
7words("I-love-you", /-/);
8// => ["I", "love", "you"]
9
10words("   ")
11// => []

sprintf(string format, ...arguments) => string

C like string formatting. Makes use of the sprintf-js package.

This function will be removed in the next major release, use the sprintf-js package instead.

1sprintf("%.1f", 1.17);
2// => "1.2"

pad(str, length, [padStr, type]) => string

pads the str with characters until the total string length is equal to the passed length parameter. By default, pads on the left with the space char (" "). padStr is truncated to a single character if necessary.

1pad("1", 8);
2// => "       1"
3
4pad("1", 8, "0");
5// => "00000001"
6
7pad("1", 8, "0", "right");
8// => "10000000"
9
10pad("1", 8, "0", "both");
11// => "00001000"
12
13pad("1", 8, "bleepblorp", "both");
14// => "bbbb1bbb"

lpad(str, length, [padStr]) => string

left-pad a string. Alias for pad(str, length, padStr, "left")

1lpad("1", 8, "0");
2// => "00000001"

rpad(str, length, [padStr]) => string

right-pad a string. Alias for pad(str, length, padStr, "right")

1rpad("1", 8, "0");
2// => "10000000"

lrpad(str, length, [padStr]) => string

left/right-pad a string. Alias for pad(str, length, padStr, "both")

1lrpad("1", 8, '0');
2// => "00001000"

toNumber(string, [decimals]) => number

Parse string to number. Returns NaN if string can't be parsed to number.

1toNumber("2.556");
2// => 3
3
4toNumber("2.556", 1);
5// => 2.6
6
7toNumber("999.999", -1);
8// => 990

strRight(string, pattern) => string

Searches a string from left to right for a pattern and returns a substring consisting of the characters in the string that are to the right of the pattern or all string if no match found.

1strRight("This_is_a_test_string", "_");
2// => "is_a_test_string"

strRightBack(string, pattern) => string

Searches a string from right to left for a pattern and returns a substring consisting of the characters in the string that are to the right of the pattern or all string if no match found.

1strRightBack("This_is_a_test_string", "_");
2// => "string"

strLeft(string, pattern) => string

Searches a string from left to right for a pattern and returns a substring consisting of the characters in the string that are to the left of the pattern or all string if no match found.

1strLeft("This_is_a_test_string", "_");
2// => "This";

strLeftBack(string, pattern) => string

Searches a string from right to left for a pattern and returns a substring consisting of the characters in the string that are to the left of the pattern or all string if no match found.

1strLeftBack("This_is_a_test_string", "_");
2// => "This_is_a_test";

stripTags(string) => string

Removes all html tags from string.

1stripTags("a <a href=\"#\">link</a>");
2// => "a link"
3
4stripTags("a <a href=\"#\">link</a><script>alert(\"hello world!\")</script>");
5// => "a linkalert("hello world!")"

toSentence(array, [delimiter, lastDelimiter]) => string

Join an array into a human readable sentence.

1toSentence(["jQuery", "Mootools", "Prototype"]);
2// => "jQuery, Mootools and Prototype";
3
4toSentence(["jQuery", "Mootools", "Prototype"], ", ", " unt ");
5// => "jQuery, Mootools unt Prototype";

toSentenceSerial(array, [delimiter, lastDelimiter]) => string

The same as toSentence, but adjusts delimeters to use Serial comma.

1toSentenceSerial(["jQuery", "Mootools"]);
2// => "jQuery and Mootools"
3
4toSentenceSerial(["jQuery", "Mootools", "Prototype"]);
5// => "jQuery, Mootools, and Prototype"
6
7toSentenceSerial(["jQuery", "Mootools", "Prototype"], ", ", " unt ");
8// => "jQuery, Mootools, unt Prototype"

repeat(string, count, [separator]) => string

Repeats a string count times.

1repeat("foo", 3);
2// => "foofoofoo"
3
4repeat("foo", 3, "bar");
5// => "foobarfoobarfoo"

surround(string, wrap) => string

Surround a string with another string.

1surround("foo", "ab");
2// => "abfooab"

quote(string, quoteChar) or q(string, quoteChar) => string

Quotes a string. quoteChar defaults to ".

1quote("foo", '"');
2// => '"foo"';

unquote(string, quoteChar) => string

Unquotes a string. quoteChar defaults to ".

1unquote('"foo"');
2// => "foo"
3
4unquote("'foo'", "'");
5// => "foo"

slugify(string) => string

Transform text into an ascii slug which can be used in safely in URLs. Replaces whitespaces, accentuated, and special characters with a dash. Limited set of non-ascii characters are transformed to similar versions in the ascii character set such as ä to a.

1slugify("Un éléphant à l\'orée du bois");
2// => "un-elephant-a-l-oree-du-bois"

Caution: this function is charset dependent

naturalCmp(string1, string2) => number

Naturally sort strings like humans would do. None numbers are compared by their ASCII values. Note: this means "a" > "A". Use .toLowerCase if this isn't to be desired.

Just past it to Array#sort.

1["foo20", "foo5"].sort(naturalCmp);
2// => ["foo5", "foo20"]

toBoolean(string) => boolean

Turn strings that can be commonly considered as booleas to real booleans. Such as "true", "false", "1" and "0". This function is case insensitive.

1toBoolean("true");
2// => true
3
4toBoolean("FALSE");
5// => false
6
7toBoolean("random");
8// => undefined

It can be customized by giving arrays of truth and falsy value matcher as parameters. Matchers can be also RegExp objects.

1toBoolean("truthy", ["truthy"], ["falsy"]);
2// => true
3
4toBoolean("true only at start", [/^true/]);
5// => true

map(string, function) => string

Creates a new string with the results of calling a provided function on every character of the given string.

1map("Hello world", function(x) {
2  return x;
3});
4// => "Hello world"
5
6map(12345, function(x) {
7  return x;
8});
9// => "12345"
10
11map("Hello world", function(x) {
12  if (x === 'o') x = 'O';
13  return x;
14});
15// => "HellO wOrld"

Library functions

If you require the full library you can use chaining and aliases

s(string) => chain

Start a chain. Returns an immutable chain object with the string functions as methods which return a new chain object instead of the plain string value.

The chain object includes also following native Javascript string methods:

• toUpperCase
• toLowerCase
• split
• replace
• slice
• substring
• substr
• concat

chain.value()

Return the string value from the chain

1s("  foo  ").trim().capitalize().value();
2// => "Foo"

When calling a method which does not return a string the resulting value is immediately returned

1s(" foobar ").trim().startsWith("foo");
2// => true

chain.tap(function) => chain

Tap into the chain with a custom function

1s("foo").tap(function(value){
2  return value + "bar";
3}).value();
4// => "foobar"

Aliases

1strip     = trim
2lstrip    = ltrim
3rstrip    = rtrim
4center    = lrpad
5rjust     = lpad
6ljust     = rpad
7contains  = include
8q         = quote
9toBool    = toBoolean
10camelcase = camelize

Maintainers

This library is maintained by

• Esa-Matti Suuronen – @epeli
• Christoph Hermann – @stoeffel

Licence

The MIT License

Copyright (c) 2011 Esa-Matti Suuronen esa-matti@suuronen.org

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.