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README.md

Install

JSON

Add to package.json file the lib as dependency.

{
  "dependencies": {
    "@feugene/mu": "^5.0"
  }
}

YARN

yarn add @feugene/mu

NPM

npm install @feugene/mu

Usage (ESM-only, Node 22+)

// Import single helper (preferred for tree-shaking)
import { number } from '@feugene/mu/format'

// Or import multiple named helpers from a submodule
import { dateToStringUTC, parseISO } from '@feugene/mu/date'

// Root imports also work (may pull more symbols depending on your bundler)
import { merge } from '@feugene/mu'

The library is ESM-first and works in modern browsers (after bundling) and Node 22+ CLI.

Import style

Prefer importing from submodules for better tree-shaking:

// Preferred: submodule imports
import { number } from '@feugene/mu/format'
import { isEmpty } from '@feugene/mu/is'
import { merge } from '@feugene/mu/object'

// Root import (valid, but may pull more code depending on bundler)
import { numberRus, defaults } from '@feugene/mu'

All examples in method pages follow this pattern: import { fn } from '@feugene/mu/<section>'.

Table of Contents

Core

Function Return Description
clone mixed Clone simple variables including array, {}-like objects, DOM nodes and Date without keeping the old reference
equals bool Deep comparing the contents of 2 elements using strict equality
forEach array, object Iterates over elements of collection and invokes iteratee for each element
keys array Creates an array of the own enumerable property names of object
match mixed It replaces such constructions as if-else and switch
tap mixed This method invokes interceptor and returns value.

Is

Function Return Example
isArguments bool isArguments([1,2]); // false
isArray bool isArray([1,2]); // true
isArrayLike bool isArrayLike('abc'); // true
isBlob bool isBlob(new Blob([])); // true
isBoolean bool isBoolean(true); // true
isBuffer bool isBuffer(Buffer.alloc(2)); // true
isDate bool isDate(new Date()); // true
isEmpty bool isEmpty(null, undefined, ''); // true
isBlank bool isBlank(' '); // true
isEmptyObject bool isEmptyObject({}); // true
isEven bool isEven(2); // true
isEvens bool isEvens(2, 4, '8'); // true
isFloat bool isFloat(2.2); // true
isFloatCanonical bool isFloatCanonical('2.0'); // true
isFloats bool isFloats('2.2','+2.1'); // true
isFunction bool isFunction(() => {}); // true
isInteger bool isInteger(12); // true
isLength bool isLength(3); // true
isNil bool isNil(undefined); // true
isNils bool isNils(null, undefined); // true
isNull bool isNull(null); // true
isNulls bool isNulls(null, undefined); // false
isNumeric bool isNumeric('1e3'); // true
isObject bool isObject([], '12', 4, Function); // false
isObjectLike bool isObjectLike([]); // true
isString bool isString('test'); // true
isSymbol bool isSymbol(Symbol('a')); // true
isTypedArray bool isTypedArray(new Uint8Array(2)); // true
isUrl bool isUrl('https://example.com'); // true

Array

Function Return Description Example
arrayEach array A specialized version of forEach for arrays arrayEach([1, '2', {}, []], (el)=>{...})
clear void Clear array
difference array The difference will output the elements from array A that are not in the array B difference([2], [1, 4, 8])); // [2]
equals bool Deep comparing the contents of 2 arrays using strict equality equals([1, '2', {}, []], [1, '2', {}, []])
intersect array Return common items for two arrays intersect([1, 2, 3, 4, 5], [1, 4, 8]); // [1,4]
intersectAll array Return common items for all arrays intersectAll([1, 2, 3, 4, 5], [1, 4, 8],[1])); // [1]
random array Random function returns random item from array random([1,2,3,4,5]]);
symmetricalDifference array will output anti-intersection symmetricalDifference([1, 2, 3, 4, 5], [1, 4, 8]); // [2, 3, 5, 8]

Object

Function Return Description Example Result
defaults object Add to source object missing properties from other sources defaults({ a: { b:2 }}, { a: { b:1, c:3 }}) {a:{ b:2, c:3 }}
objectsEqual bool Deep comparing the contents of 2 or more object using strict equality equals({k: 1, v: [1,2,{}]}, {k: 1, v: [1,2,{}]})
filter object Filter props in Object filter({key1:1, key:4}, ([key, value])=>value > 1) {key:4}
flip object Swap key with value swap({a:1, b:'test', c:3}) {1:'a', 'test':'b', 3:'c'}
fromQueryString object Converts a query string back into an object fromQueryString('foo=1&bar=2')
getSize int Returns count of properties of the object getSize({k: 1, v: []})
logicalAnd boolean Logical AND by object's values logicalAnd({ a: true, b: true, c: false }) false
merge object Merge 2 or more objects recursively merge({k: 1}, {v: 'test'}, {k: 2})
pathToObject object Return Object from sting path pathToObject('key.sub', 1) {key:{sub:1}}
pick object Creates an object composed of the picked object properties. pick({a:1, b:2, c:3}, ['a', 'b'])
remove object Remove value by deep key in object(array) remove(obj, 'key.sub.items.1')
removeEmpty object Removes all empty values in an object recursively removeEmpty({val:'hi', val2:null, val3:{}}) {val:'hi'}
select mixed Get value by deep key in object(array) select(obj, 'key.sub.items.1')
sum Number Sum of object's values sum({ a: 1, b: 2, c: 3 }) 6
toQueryObjects object Converts a name - value pair to an array of objects with support for nested structure toQueryObjects('hobbies', ['reading', 'cooking', 'swimming'])
toQueryString string Takes an object and converts it to an encoded query string toQueryString({colors: ['red', 'green', 'blue']}
values array Creates an array of the own enumerable string keyed property values of object values('hi') ['h','i']

To

Function Return Description Example
toArray array Converts value to a array toArray('test') // ['t','e','s','t']
toFinite int Converts value to a finite integer toFinite('-3.2') // 3
toInteger int Converts value to a integer toInteger('3.2') // 3
toNumber int Converts value to a number toNumber('3.2') // 3.2
toString string Converts value to a string toString(1234) // '1234'

Sort

Function Return Description Example
sortObjectsInArrayByProperty array-object Allows to sort an array into an objects by key sortObjectsInArrayByProperty(object, 'list.title')
sortDescObjectsInArrayByProperty array-object Allows to sort (DESC) an array into an objects by key sortDescObjectsInArrayByProperty(object, 'list.title')

String

Function Return Description
camelCase string Convert a dash/dot/underscore/space separated string to camelCase
clearSpaces string Remove extra spaces from string
endsWith string Checks if string ends with the given target string
hasUnicode bool Checks if string contains Unicode symbols
normalizeCustom string Normalize string by custom RegExp
normalizeName string Normalize string by RegExp [^0-9a-zA-Z_]
normalizeKebab string Normalize string to kebab (by RegExp [^0-9a-zA-Z\-])
padStart string add leading symbols
padEnd string add ending symbols
pascalCase string Convert a dash/dot/underscore/space separated string to PascalCase
removeConsecutiveDuplicates string Remove consecutive duplicates
replaceByTemplate string Translate characters or replace substrings in string by map
startsWith string Checks if string starts with the given target string
stringToArray string Converts string to an array
strtr string Translate characters or replace substrings in string
titleCase string Converts the first character of every word into string to upper case
trim string Trim leading and trailing whitespace
trimAny string Trim any characters
trimPrefix string Remove a prefix from a target string
trimSuffix string Remove a suffix from a target string
upperFirst string Converts the first character of string to upper case

Date

Function Return Description
elapsed number Difference in milliseconds between dates
now number Current time in ms since UNIX epoch
dateToString string Local time YYYY-MM-DDTHH:mm:SS (no timezone suffix)
dateToStringUTC string UTC time YYYY-MM-DDTHH:mm:SSZ
parseISO Date|null Strict ISO/RFC3339 or epoch ms string → Date; else null

Format

Function Return Description Example
fileSize string Display number as file size fileSize(7900221323) // '7.36 Gb'
intWord string Compact integer with unit suffix intWord(21323) // '21.32K'
number string Formatting number (options supported) number('10000') // '10,000.00'
numberRus string RU format: space group, comma as decimal numberRus(1001.2) // '1 001,20'
padDateTime string Zero-pad date/time part to 2 chars padDateTime(1) // '01'
padNumber string Left-pad a number with zeros to width N padNumber(2,3) // '002'

Utilities

Function Return Description
b64ToUtf8 string Decode string from base-64 to Unicode
b64ToUtf8Safe string Decode from safe base-64 to Unicode string
times string Invokes the iteratee n times, returning an array of the results of each invocation
utf8ToB64 string Encode string from Unicode to base-64
utf8Tob64Safe string Encode from Unicode string to safe base-64

Structures

  • Stack
  • Queue

Behavior changes in v5

Compared to earlier major versions, v5 introduces clearer, safer semantics:

  • Object helpers

    • merge and defaults are now immutable: they return new objects instead of mutating inputs.
    • Both ignore dangerous keys ("__proto__", "prototype", "constructor") to prevent prototype pollution.
    • Deep merge/defaults apply only to plain objects; arrays are cloned but not merged element-wise.

  • Clone

    • clone uses native structuredClone where safe (Node 22+/modern browsers) with a predictable fallback for plain objects/arrays and Dates.

  • Date

    • parseISO is a strict parser: accepts only ISO/RFC3339 or epoch-ms strings, returns null for ambiguous formats.
    • dateToString (local) и dateToStringUTC (UTC) теперь явно документируют таймзону и формат.

  • Format

    • number / numberRus корректно обрабатывают NaN, Infinity, -0, имеют options-object API и стабильную локальную семантику (numberRus: запятая как десятичный разделитель, пробел — тысячный).

See individual method pages for more details and examples.

Documentation quality and checks

To keep documentation in sync with code:

  • All helpers listed in the tables above have dedicated pages in docs/<section>/*.md.
  • Tables link only to existing files; new helpers should be added to both the table and their own method page.

Recommended future automation (not included in the package, но легко добавить в CI):

  • Script that scans docs/README.md and docs/ru/README.md and verifies that every linked file exists.
  • Optional type-level tests (e.g. via tsd) that compile Use-examples from docs to ensure signatures stay valid.

Test

jest

or

yarn test