utils

Fast, generic JavaScript/node.js utility functions.

Install with npm

$ npm i utils --save

Usage

Utils grouped by collection

The top level export gives you an object with utils grouped into collections, like array, object, math, etc:

var utils = require('utils');
//=> {array: {flatten: [function], ...}, collection: {...}}

See example.md for an example of the utils object.

Get all utils on one object

If you want all utils on a single object (e.g. not grouped by collection):

// all utils are on the `_` property
var utils = require('utils')._;

Only get a specific collection

If you just want the string or object utils:

var string = require('utils').string;
var object = require('utils').object;

API

.after

Returns all of the items in an array after the specified index.

Params

array {Array}: Collection
n {Number}: Starting index (number of items to exclude)
returns {Array}: Array exluding n items.

Example

after(['a', 'b', 'c'], 1)
//=> ['c']

.arrayify

Cast the give value to an array.

Params

val {*}
returns {Array}

Example

arrayify('abc')
//=> ['abc']

arrayify(['abc'])
//=> ['abc']

.before

Returns all of the items in an array up to the specified number Opposite of <%= after() %.

Params

array {Array}
n {Number}
returns {Array}: Array excluding items after the given number.

Example

before(['a', 'b', 'c'], 2)
//=> ['a', 'b']

.compact

Remove all falsey values from an array.

Params

arr {Array}
returns {Array}

Example

compact([null, a, undefined, 0, false, b, c, '']);
//=> [a, b, c]

.difference

Return the difference between the first array and additional arrays.

Params

a {Array}
b {Array}
returns {Array}

Example

var a = ['a', 'b', 'c', 'd'];
var b = ['b', 'c'];

diff(a, b);
//=> ['a', 'd']

.each

Loop over each item in an array and call the given function on every element.

Params

array {Array}
fn {Function}
thisArg {Object}: Optionally pass a thisArg to be used as the context in which to call the function.
returns {Array}

Example

each(['a', 'b', 'c'], function (ele) {
  return ele + ele;
});
//=> ['aa', 'bb', 'cc']

each(['a', 'b', 'c'], function (ele, i) {
  return i + ele;
});
//=> ['0a', '1b', '2c']

.first

Returns the first item, or first n items of an array.

Params

array {Array}
n {Number}: Number of items to return, starting at 0.
returns {Array}

Example

first(['a', 'b', 'c', 'd', 'e'], 2)
//=> ['a', 'b']

.flatten

Recursively flatten an array or arrays. Uses the fastest implementation of array flatten for node.js

Params

array {Array}
returns {Array}: Flattened array

Example

flatten(['a', ['b', ['c']], 'd', ['e']]);
//=> ['a', 'b', 'c', 'd', 'e']

.forEach

Loop over each item in an array and call the given function on every element.

Params

array {Array}
fn {Function}
thisArg {Object}: Optionally pass a thisArg to be used as the context in which to call the function.
returns {Array}

Example

forEach(['a', 'b', 'c'], function (ele) {
  return ele + ele;
});
//=> ['aa', 'bb', 'cc']

forEach(['a', 'b', 'c'], function (ele, i) {
  return i + ele;
});
//=> ['0a', '1b', '2c']

.isArray

Returns true if the given value is an array.

Params

value {Array}: Value to test.

Example

isArray(1);
//=> 'false'

isArray([1]);
//=> 'true'

.last

Returns the last item, or last n items of an array.

Params

array {Array}
n {Number}: Number of items to return, starting with the last item.
returns {Array}

Example

last(['a', 'b', 'c', 'd', 'e'], 2)
//=> ['d', 'e']

.map

Returns a new array with the results of calling the given function on every element in the array. This is a faster, node.js focused alternative to JavaScript's native array map.

Params

array {Array}
fn {Function}
returns {Array}

Example

map(['a', 'b', 'c'], function (ele) {
  return ele + ele;
});
//=> ['aa', 'bb', 'cc']

map(['a', 'b', 'c'], function (ele, i) {
  return i + ele;
});
//=> ['0a', '1b', '2c']

.slice

Alternative to JavaScript's native array-slice method. Slices array from the start index up to but not including the end index.

Params

array {Array}: the array to slice.
start {Number}: Optionally define the starting index.
end {Number}: Optionally define the ending index.

Example

var arr = ['a', 'b', 'd', 'e', 'f', 'g', 'h', 'i', 'j'];

slice(arr, 3, 6);
//=> ['e', 'f', 'g']

.union

Return an array free of duplicate values. Fastest ES5 implementation.

Params

array {Array}: The array to uniquify
returns {Array}: With all union values.

Example

union(['a', 'b', 'c', 'c']);
//=> ['a', 'b', 'c']

.unique

Return an array free of duplicate values. Fastest ES5 implementation.

Params

array {Array}: The array to uniquify
returns {Array}: With all unique values.

Example

unique(['a', 'b', 'c', 'c']);
//=> ['a', 'b', 'c']

.any

Returns true if value exists in the given string, array or object. See [any] for documentation.

Params

value {*}
target {*}
options {Object}

.contains

Return true if collection contains value

Params

collection {Array|Object}
string {*}
returns {Boolean}

.tryRead

Try to read the given filepath, fail silently and return null when a file doesn't exist. Slightly faster than using fs.existsSync.

Params

fp {String}: Path of the file to read.
returns {String|Null}: the utf8 contents string, or null if an error is thrown.

.tryReaddir

Try to read the given directory. Wraps fs.readdirSync() with a try/catch, so it fails silently instead of throwing when the directory doesn't exist.

Params

dir {String}: Starting directory
returns {Array}: Array of files.

.tryRequire

Try to require the given file, returning null if not successful instead of throwing an error.

Params

fp {String}: File path of the file to require
returns {*}: Returns the module function/object, or null if not found.

.identity

Returns the first argument passed to the function.

returns {*}

.noop

A "no-operation" function. Returns undefined regardless of the arguments it receives.

returns {undefined}

.partialRight

Partially applies arguments that will be appended to those provided to the returned function.

Params

ctx {Object}: Optionally supply an invocation context for the returned function.
fn {Function}: The function to which arguments should be partially applied.
arguments __{...}*: List of arguments to be partially applied.
returns {Function}: Returns a function with partially applied arguments.

Example

function fullname(first, last) {
  return first + ' ' + last;
}

var name = partialRight(fn, 'Woodward');
name('Brian');
//=> 'Brian Woodward'

.hasValues

Returns true if any value exists, false if empty. Works for booleans, functions, numbers, strings, nulls, objects and arrays.

Params

object {Object}: The object to check for value
value {*}: the value to look for
returns {Boolean}: True if any values exists.

Example

hasValues('a');
//=> true

hasValues('');
//=> false

hasValues(1);
//=> true

hasValues({a: 'a'}});
//=> true

hasValues({}});
//=> false

hasValues(['a']);
//=> true

.isEmpty

Returns true if the given value is empty, false if any value exists. Works for booleans, functions, numbers, strings, nulls, objects and arrays.

Params

object {Object}: The object to check for value
value {*}: the value to look for
returns {Boolean}: False if any values exists.

Example

isEmpty('a');
//=> false

isEmpty('');
//=> true

isEmpty(1);
//=> false

isEmpty({a: 'a'});
//=> false

isEmpty({});
//=> true

isEmpty(['a']);
//=> false

.isObject

Return true if the given value is an object with keys.

Params

value {Object}: The value to check.
returns {Boolean}

Example

isObject(['a', 'b', 'c'])
//=> 'false'

isObject({a: 'b'})
//=> 'true'

.isPlainObject

Return true if the given value is an object with keys.

Params

value {Object}: The value to check.
returns {Boolean}

Example

isPlainObject(Object.create({}));
//=> true
isPlainObject(Object.create(Object.prototype));
//=> true
isPlainObject({foo: 'bar'});
//=> true
isPlainObject({});
//=> true

.sum

Returns the sum of all numbers in the given array.

Params

array {Array}: Array of numbers to add up.
returns {Number}

Example

sum([1, 2, 3, 4, 5])
//=> '15'

.defaults

Extend object with properties of other objects

Params

object {Object}: The target object. Pass an empty object to shallow clone.
objects {Object}
returns {Object}

.extend

Extend o with properties of other objects.

Params

o {Object}: The target object. Pass an empty object to shallow clone.
objects {Object}
returns {Object}

.functions

Returns a copy of the given obj filtered to have only enumerable properties that have function values.

Params

obj {Object}
returns {Object}

Example

functions({a: 'b', c: function() {}});
//=> {c: function() {}}

.hasOwn

Return true if key is an own, enumerable property of the given obj.

Params

key {String}
obj {Object}: Optionally pass an object to check.
returns {Boolean}

Example

hasOwn(obj, key);

.keys

Return an array of keys for the given obj. Uses Object.keys when available, otherwise falls back on forOwn.

Params

obj {Object}
returns {Array}: Array of keys.

mapValues

Returns new object where each value is the result of calling the a callback function.

Params

{Object}: obj The object to iterate over
cb {Function}: Callback function
{Object}: thisArg Invocation context of cb
returns {Object}

.merge

Recursively combine the properties of o with the properties of other objects.

Params

o {Object}: The target object. Pass an empty object to shallow clone.
objects {Object}
returns {Object}

.methods

Returns a list of all enumerable properties of obj that have function values

Params

obj {Object}
returns {Array}

.reduce

Reduces an object to a value that is the accumulated result of running each property in the object through a callback.

Params

obj {Object}: The object to iterate over.
iterator {Function}: Iterator function
initial {Object}: Initial value.
thisArg {Object}: The this binding of the iterator function.
returns {Object}

Example

var a = {a: 'foo', b: 'bar', c: 'baz'};

reduce(a, function (acc, value, key, obj) {
  // `acc`- the initial value (or value from the previous callback call),
  // `value`- the of the current property,
  // `key`- the of the current property, and
  // `obj` - original object

  acc[key] = value.toUpperCase();
  return acc;
}, {});

//=> {a: 'FOO', b: 'BAR', c: 'BAZ'};

.camelcase

camelCase the characters in string.

Params

string {String}: The string to camelcase.
returns {String}

Example

camelcase("foo bar baz");
//=> 'fooBarBaz'

.centerAlign

Center align the characters in a string using non-breaking spaces.

Params

str {String}: The string to reverse.
returns {String}: Centered string.

Example

centerAlign("abc");

.chop

Like trim, but removes both extraneous whitespace and non-word characters from the beginning and end of a string.

Params

string {String}: The string to chop.
returns {String}

Example

chop("_ABC_");
//=> 'ABC'

chop("-ABC-");
//=> 'ABC'

chop(" ABC ");
//=> 'ABC'

.count

Count the number of occurrances of a substring within a string.

Params

string {String}
substring {String}
returns {Number}: The occurances of substring in string

Example

count("abcabcabc", "a");
//=> '3'

.dashcase

dash-case the characters in string. This is similar to [slugify], but [slugify] makes the string compatible to be used as a URL slug.

Params

string {String}
returns {String}

Example

dashcase("a b.c d_e");
//=> 'a-b-c-d-e'

.dotcase

dot.case the characters in string.

Params

string {String}
returns {String}

Example

dotcase("a-b-c d_e");
//=> 'a.b.c.d.e'

.ellipsis

Truncate a string to the specified length, and append it with an elipsis, ….

Params

str {String}
length {Number}: The desired length of the returned string.
ch {String}: Optionally pass custom characters to append. Default is ….
returns {String}: The truncated string.

Example

ellipsis("<span>foo bar baz</span>", 7);
//=> 'foo bar…'

.hyphenate

Replace spaces in a string with hyphens. This

Params

string {String}
returns {String}

Example

hyphenate("a b c");
//=> 'a-b-c'

.isString

Returns true if the value is a string.

Params

val {String}
returns {Boolean}: True if the value is a string.

Example

isString('abc');
//=> 'true'

isString(null);
//=> 'false'

.pascalcase

PascalCase the characters in string.

Params

string {String}
returns {String}

Example

pascalcase("foo bar baz");
//=> 'FooBarBaz'

.pathcase

path/case the characters in string.

Params

string {String}
returns {String}

Example

pathcase("a-b-c d_e");
//=> 'a/b/c/d/e'

.replace

Replace occurrences of a with b.

Params

str {String}
a {String|RegExp}: Can be a string or regexp.
b {String}
returns {String}

Example

replace("abcabc", /a/, "z");
//=> 'zbczbc'

.reverse

Reverse the characters in a string.

Params

str {String}: The string to reverse.
returns {String}

Example

reverse("abc");
//=> 'cba'

.rightAlign

Right align the characters in a string using non-breaking spaces.

Params

str {String}: The string to reverse.
returns {String}: Right-aligned string.

Example

rightAlign(str);

.sentencecase

Sentence-case the characters in string.

Params

string {String}
returns {String}

Example

sentencecase("foo bar baz.");
//=> 'Foo bar baz.'

.snakecase

snake_case the characters in string.

Params

string {String}
returns {String}

Example

snakecase("a-b-c d_e");
//=> 'a_b_c_d_e'

.truncate

Truncate a string by removing all HTML tags and limiting the result to the specified length.

Params

str {String}
length {Number}: The desired length of the returned string.
returns {String}: The truncated string.

Example

truncate("<span>foo bar baz</span>", 7);
//=> 'foo bar'

.wordwrap

Wrap words to a specified width using [word-wrap].

Params

string {String}: The string with words to wrap.
object {Options}: Options to pass to [word-wrap]
returns {String}: Formatted string.

Example

wordwrap("a b c d e f", {width: 5, newline: '<br>  '});
//=> '  a b c <br>  d e f'

Code coverage

Please help improve code coverage by adding unit tests.

-----------------------|----------|----------|----------|----------|----------------|
File                   |  % Stmts | % Branch |  % Funcs |  % Lines |Uncovered Lines |
-----------------------|----------|----------|----------|----------|----------------|
 utils/                |      100 |      100 |      100 |      100 |                |
  index.js             |      100 |      100 |      100 |      100 |                |
 utils/lib/            |      100 |      100 |      100 |      100 |                |
  index.js             |      100 |      100 |      100 |      100 |                |
 utils/lib/array/      |    91.75 |    83.33 |      100 |    92.55 |                |
  after.js             |      100 |       75 |      100 |      100 |                |
  arrayify.js          |      100 |      100 |      100 |      100 |                |
  before.js            |      100 |       75 |      100 |      100 |                |
  compact.js           |      100 |      100 |      100 |      100 |                |
  difference.js        |      100 |      100 |      100 |      100 |                |
  each.js              |      100 |      100 |      100 |      100 |                |
  first.js             |    88.89 |    83.33 |      100 |    88.24 |          27,46 |
  flatten.js           |      100 |      100 |      100 |      100 |                |
  forEach.js           |      100 |      100 |      100 |      100 |                |
  index.js             |      100 |      100 |      100 |      100 |                |
  indexOf.js           |    76.92 |       70 |      100 |    83.33 |          23,40 |
  isArray.js           |      100 |      100 |      100 |      100 |                |
  last.js              |    88.89 |    83.33 |      100 |    88.24 |          27,46 |
  map.js               |      100 |      100 |      100 |      100 |                |
  slice.js             |      100 |      100 |      100 |      100 |                |
  sort.js              |    90.91 |     87.5 |      100 |    90.91 |             27 |
  union.js             |      100 |      100 |      100 |      100 |                |
  unique.js            |      100 |      100 |      100 |      100 |                |
 utils/lib/collection/ |    55.56 |        0 |        0 |    55.56 |                |
  any.js               |      100 |      100 |      100 |      100 |                |
  contains.js          |    42.86 |        0 |        0 |    42.86 |    18,19,21,22 |
  index.js             |      100 |      100 |      100 |      100 |                |
 utils/lib/fs/         |    68.75 |      100 |    66.67 |    68.75 |                |
  index.js             |      100 |      100 |      100 |      100 |                |
  tryRead.js           |       40 |      100 |        0 |       40 |       16,17,19 |
  tryReaddir.js        |       80 |      100 |      100 |       80 |             20 |
  tryRequire.js        |       80 |      100 |      100 |       80 |             19 |
 utils/lib/function/   |    36.36 |        0 |        0 |    36.36 |                |
  identity.js          |       50 |      100 |        0 |       50 |             12 |
  index.js             |      100 |      100 |      100 |      100 |                |
  noop.js              |       50 |      100 |        0 |       50 |             13 |
  partialRight.js      |    16.67 |        0 |        0 |    16.67 | 26,27,28,29,30 |
 utils/lib/lang/       |      100 |      100 |      100 |      100 |                |
  hasValues.js         |      100 |      100 |      100 |      100 |                |
  index.js             |      100 |      100 |      100 |      100 |                |
  isEmpty.js           |      100 |      100 |      100 |      100 |                |
  isObject.js          |      100 |      100 |      100 |      100 |                |
  isPlainObject.js     |      100 |      100 |      100 |      100 |                |
  typeOf.js            |      100 |      100 |      100 |      100 |                |
 utils/lib/math/       |      100 |      100 |      100 |      100 |                |
  index.js             |      100 |      100 |      100 |      100 |                |
  sum.js               |      100 |      100 |      100 |      100 |                |
 utils/lib/object/     |    62.77 |    46.15 |    17.65 |    61.96 |                |
  defaults.js          |      100 |      100 |      100 |      100 |                |
  extend.js            |      100 |    83.33 |      100 |      100 |                |
  filter.js            |      100 |      100 |      100 |      100 |                |
  forIn.js             |      100 |      100 |      100 |      100 |                |
  forOwn.js            |      100 |      100 |      100 |      100 |                |
  functions.js         |    28.57 |        0 |        0 |    28.57 | 21,23,24,25,29 |
  hasOwn.js            |      100 |      100 |      100 |      100 |                |
  index.js             |      100 |      100 |      100 |      100 |                |
  keys.js              |    33.33 |       50 |        0 |    33.33 |    16,17,18,20 |
  mapValues.js         |     37.5 |      100 |        0 |     37.5 | 18,19,21,22,25 |
  merge.js             |      100 |       75 |      100 |      100 |                |
  methods.js           |    28.57 |        0 |        0 |    28.57 | 16,18,19,20,24 |
  omit.js              |      100 |      100 |      100 |      100 |                |
  pick.js              |      100 |      100 |      100 |      100 |                |
  pluck.js             |       75 |      100 |        0 |       75 |             17 |
  prop.js              |    33.33 |      100 |        0 |    33.33 |            4,5 |
  reduce.js            |      100 |      100 |      100 |      100 |                |
  result.js            |       25 |        0 |        0 |       25 | 6,7,8,10,11,13 |
  some.js              |       30 |        0 |        0 |       30 |... 11,12,13,16 |
 utils/lib/string/     |    99.28 |    96.77 |       96 |     99.1 |                |
  camelcase.js         |      100 |      100 |      100 |      100 |                |
  centerAlign.js       |      100 |      100 |      100 |      100 |                |
  chop.js              |      100 |      100 |      100 |      100 |                |
  count.js             |      100 |      100 |      100 |      100 |                |
  dashcase.js          |      100 |      100 |      100 |      100 |                |
  dotcase.js           |      100 |      100 |      100 |      100 |                |
  ellipsis.js          |      100 |      100 |      100 |      100 |                |
  hyphenate.js         |      100 |      100 |      100 |      100 |                |
  index.js             |      100 |      100 |      100 |      100 |                |
  isString.js          |      100 |      100 |      100 |      100 |                |
  pascalcase.js        |      100 |      100 |      100 |      100 |                |
  pathcase.js          |      100 |      100 |      100 |      100 |                |
  replace.js           |      100 |      100 |      100 |      100 |                |
  reverse.js           |      100 |      100 |      100 |      100 |                |
  rightAlign.js        |      100 |      100 |      100 |      100 |                |
  sentencecase.js      |      100 |      100 |      100 |      100 |                |
  slugify.js           |      100 |      100 |      100 |      100 |                |
  snakecase.js         |      100 |      100 |      100 |      100 |                |
  toString.js          |       50 |        0 |        0 |       50 |             10 |
  truncate.js          |      100 |      100 |      100 |      100 |                |
  wordwrap.js          |      100 |      100 |      100 |      100 |                |
-----------------------|----------|----------|----------|----------|----------------|
All files              |    84.54 |    80.52 |    67.16 |    83.43 |                |
-----------------------|----------|----------|----------|----------|----------------|

Running tests

Install dev dependencies:

$ npm i -d && npm test

Contributing

Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.

Adding utils

If you want to do a PR to add a util, please read the following first:

follow the same coding style as the rest of the library, same with code comments
add sufficient unit tests
Install dev dependencies and run verb
Look over the README to make sure that verb rendered out the docs with your method and code comments.

Adding external modules as dependencies

External modules will only be considered if they meet the same quality and coding standards as the rest of the library. At minimum this includes documentation, code comments, and unit tests. Benchmarks are also strongly preferred.

Updating the docs

Do not edit the readme manually since verbis used to generate documentation.

API docs: If you see an error in the API documentation, just update the code comments for that method, then run verb.
Everything else, please look over the .verb.md template to see where the error is, then run verb.

Running verb

Install dev dependencies, then run verb:

$ npm install -d && verb

About

Why another utils lib?

I'm a node.js developer. I want fast, light, dependable utility functions for node.js projects.
Do you really need bloated, everything-but-the-kitchen-sink functions that are guaranteed to work with IE 4, for your Yeoman generator or gulp plugin!? Nonsense.
The benchmarks that accompany many of the functions in the library show that in some cases, the penalty for using such "kitchen-sink" code is a 2,000-5,000% reduction in speed. Sometimes greater.

Project goals

Fastest implementation of each method, without too much compromise. Covering uncommon cases is fine, but don't go overboard.
Clean well-documented, commented code.
When it makes sense, external libraries are used and exposed instead of writing new code.
Focus on node.js usage and projects that are likely to use a number of these utils in one project. If you only need one or two of these in a small project, don't use this. Use small modules that do only one thing.

Related projects

This project depends on these great libraries. If you don't need a full utility belt for your project, any of these can be used by themselves:

any: Returns true if a value exists in the given string, array or object. | homepage
arr-diff: Returns an array with only the unique values from the first array, by excluding all… more | homepage
arr-flatten: Recursively flatten an array or arrays. This is the fastest implementation of array flatten. | homepage
arr-map: Faster, node.js focused alternative to JavaScript's native array map. | homepage
arr-union: Combines a list of arrays, returning a single array with unique values, using strict equality… more | homepage
array-each: Loop over each item in an array and call the given function on every element. | homepage
array-slice: Array-slice method. Slices array from the start index up to, but not including, the end… more | homepage
array-unique: Return an array free of duplicate values. Fastest ES5 implementation. | homepage
center-align: Center-align the text in a string. | homepage
export-dirs: Export directories and their files as node.js modules. | homepage
export-files: node.js utility for exporting a directory of files as modules. | homepage
for-in: Iterate over the own and inherited enumerable properties of an objecte, and return an object… more | homepage
for-own: Iterate over the own enumerable properties of an object, and return an object with properties… more | homepage
has-values: Returns true if any values exist, false if empty. Works for booleans, functions, numbers, strings,… more | homepage
is-number: Returns true if the value is a number. comprehensive tests. | homepage
is-plain-object: Returns true if an object was created by the Object constructor. | homepage
kind-of: Get the native type of a value. | homepage
make-iterator: Convert an argument into a valid iterator. Based on the .makeIterator() implementation in mout https://github.com/mout/mout. | homepage
object.defaults: Like extend but only copies missing properties/values to the target object. | homepage
object.filter: Create a new object filtered to have only properties for which the callback returns true. | homepage
object.omit: Return a copy of an object excluding the given key, or array of keys. Also… more | homepage
object.pick: Returns a filtered copy of an object with only the specified keys, like pick from… more | homepage
object.reduce: Reduces an object to a value that is the accumulated result of running each property… more | homepage
right-align: Right-align the text in a string. | homepage
striptags: PHP strip_tags in Node.js | homepage
word-wrap: Wrap words to a specified length. | homepage

Author

Jon Schlinkert

License

This file was generated by verb-cli on September 23, 2015.

utils

TOC

Usage

API

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