utils

Fast, generic JavaScript/node.js utility functions.

Install with npm

$ npm i utils --save

TOC

• Usage
• API
• Code coverage
• Running tests
• Contributing
  • Adding utils
  • Updating the docs
  • Running verb
• About
• Related projects
• Author
• License

(Table of contents generated by verb)

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

• github/jonschlinkert
• twitter/jonschlinkert

License

Copyright © 2015 Jon Schlinkert Released under the MIT license.

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