underscore.string

String manipulation extensions for Underscore.js javascript library.

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

Underscore.string

Javascript lacks complete string manipulation operations. This 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.

Install from npm

npm install underscore.string

Require individual functions

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

or load the full library to enable chaining

var s = require("underscore.string");
 
s("   epeli  ").trim().capitalize().value();
// => "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.

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.

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

_.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.

Formats the numbers.

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

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

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

Converts first letter of the string to uppercase.

capitalize("foo Bar");
// => "Foo Bar" 

Converts first letter of the string to lowercase.

decapitalize("Foo Bar");
// => "foo Bar" 
chop("whitespace", 3);
// => ["whi", "tes", "pac", "e"] 

Trim and replace multiple spaces with a single space.

clean(" foo    bar   ");
// => "foo bar" 
chars("Hello");
// => ["H", "e", "l", "l", "o"] 

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

swapCase("hELLO");
// => "Hello" 

Tests if string contains a substring.

include("foobar", "ob");
// => true 
count("Hello world", "l");
// => 3 

Converts HTML special characters to their entity equivalents.

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

Converts entity characters to HTML equivalents.

unescapeHTML("&lt;div&gt;Blah blah blah&lt;/div&gt;");
// => "<div>Blah blah blah</div>" 
insert("Hello ", 6, "world");
// => "Hello world" 
replaceAll("foo", "o", "a");
// => "faa" 
isBlank(""); // => true 
isBlank("\n"); // => true 
isBlank(" "); // => true 
isBlank("a"); // => false 

Joins strings together with given separator

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

Split lines to an array

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

Dedent unnecessary indentation or dedent by a pattern.

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

dedent("  Hello\n    World");
// => "Hello\n  World" 
 
dedent("\t\tHello\n\t\t\t\tWorld");
// => "Hello\n\t\tWorld" 
 
dedent("    Hello\n    World", "  "); // Dedent by 2 spaces 
// => "  Hello\n  World" 

Return reversed string:

reverse("foobar");
// => "raboof" 

Like an array splice.

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

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

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

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

endsWith("image.gif", "gif");
// => true 
 
endsWith("image.old.gif", "old", 9);
// => true 

Returns the predecessor to str.

pred("b");
// => "a" 
 
pred("B");
// => "A" 

Returns the successor to str.

succ("a");
// => "b" 
 
succ("A");
// => "B" 
titleize("my name is epeli");
// => "My Name Is Epeli" 

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.

camelize("moz-transform");
// => "mozTransform" 
 
camelize("-moz-transform");
// => "MozTransform" 
 
camelize("_moz_transform");
// => "MozTransform" 
 
camelize("Moz-transform");
// => "MozTransform" 
 
camelize("-moz-transform", true);
// => "mozTransform" 

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

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

Converts a camelized or dasherized string into an underscored one

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

Converts a underscored or camelized string into an dasherized one

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

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

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

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

trim("  foobar   ");
// => "foobar" 
 
trim("_-foobar-_", "_-");
// => "foobar" 

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

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

truncate("Hello world", 5);
// => "Hello..." 
 
truncate("Hello", 10);
// => "Hello" 

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

prune("Hello, world", 5);
// => "Hello..." 
 
prune("Hello, world", 8);
// => "Hello..." 
 
prune("Hello, world", 5, " (read a lot more)");
// => "Hello, world" (as adding "(read a lot more)" would be longer than the original string) 
 
prune("Hello, cruel world", 15);
// => "Hello, cruel..." 
 
prune("Hello", 10);
// => "Hello" 

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

words("   I   love   you   ");
// => ["I", "love", "you"] 
 
words("I_love_you", "_");
// => ["I", "love", "you"] 
 
words("I-love-you", /-/);
// => ["I", "love", "you"] 
 
words("   ")
// => [] 

C like string formatting. Credits goes to Alexandru Marasteanu. For more detailed documentation, see the original page.

sprintf("%.1f", 1.17);
// => "1.2" 

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.

pad("1", 8);
// => "       1" 
 
pad("1", 8, "0");
// => "00000001" 
 
pad("1", 8, "0", "right");
// => "10000000" 
 
pad("1", 8, "0", "both");
// => "00001000" 
 
pad("1", 8, "bleepblorp", "both");
// => "bbbb1bbb" 

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

lpad("1", 8, "0");
// => "00000001" 

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

rpad("1", 8, "0");
// => "10000000" 

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

lrpad("1", 8, '0');
// => "00001000" 

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

toNumber("2.556");
// => 3 
 
toNumber("2.556", 1);
// => 2.6 
 
toNumber("999.999", -1);
// => 990 

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.

strRight("This_is_a_test_string", "_");
// => "is_a_test_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.

strRightBack("This_is_a_test_string", "_");
// => "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.

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

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.

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

Removes all html tags from string.

stripTags("a <a href="#">link</a>");
// => "a link" 
 
stripTags("a <a href="#">link</a><script>alert("hello world!")</script>");
// => "a linkalert("hello world!")" 

Join an array into a human readable sentence.

toSentence(["jQuery", "Mootools", "Prototype"]);
// => "jQuery, Mootools and Prototype"; 
 
toSentence(["jQuery", "Mootools", "Prototype"], "", " unt ');
// => "jQuery, Mootools unt Prototype";

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

toSentenceSerial(["jQuery", "Mootools"]);
// => "jQuery and Mootools" 
 
toSentenceSerial(["jQuery", "Mootools", "Prototype"]);
// => "jQuery, Mootools, and Prototype" 
 
toSentenceSerial(["jQuery", "Mootools", "Prototype"], "", " unt ');
// => "jQuery, Mootools, unt Prototype"

Repeats a string count times.

repeat("foo", 3);
// => "foofoofoo" 
 
repeat("foo", 3, "bar");
// => "foobarfoobarfoo" 

Surround a string with another string.

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

Quotes a string. quoteChar defaults to ".

quote("foo", '"');
// => '"foo"'; 

Unquotes a string. quoteChar defaults to ".

unquote('"foo"');
// => "foo" 
 
unquote("'foo'", "'");
// => "foo" 

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.

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

Caution: this function is charset dependent

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.

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

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

toBoolean("true");
// => true 
 
toBoolean("FALSE");
// => false 
 
toBoolean("random");
// => undefined 

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

toBoolean("truthy", ["truthy"], ["falsy"]);
// => true 
 
toBoolean("true only at start", [/^true/]);
// => true 

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

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:

Return the string value from the chain

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

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

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

Tap into the chain with a custom function

s("foo").tap(function(value){
  return value + "bar";
}).value();
// => "foobar" 
strip     = trim
lstrip    = ltrim
rstrip    = rtrim
center    = lrpad
rjust     = lpad
ljust     = rpad
contains  = include
q         = quote
toBool    = toBoolean
camelcase = camelize

This library is maintained by

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.