string-kit-js

Simple string utility functions for JavaScript/Node.js

Current API groups

• Blank/empty checks: isBlank, isEmpty, isNotBlank, isNotEmpty
• Compare/null-safe: equals, equalsIgnoreCase, compare
• Search/index: contains, indexOf, lastIndexOf, indexOfAny, lastIndexOfAny, indexOfAnyBut, lastIndexOfAnyBut
• Character checks: containsOnly, containsNone, containsAny, isAlpha, isNumeric, isWhitespace, isAsciiPrintable
• Extract: substring, left, right, mid, substringBefore, substringAfter, substringBetween, substringBeforeLast, substringAfterLast
• Split/join: split, join
• Replace/remove: remove, deleteSubstring, replace, overlay
• Ending/prefix helpers: appendIfMissing, prependIfMissing
• Pad/repeat/layout: leftPad, rightPad, center, repeat
• Case/normalize: toUpper, toLower, swapCase, capitalize, uncapitalize, normalizeSpace, stripAccents, toCamelCase, toKebabCase, toSnakeCase
• Other transforms: trim, trimToNull, trimToEmpty, chomp, chop, rotate, reverse, reverseDelimited, truncate, abbreviate
• Defaults/diff/distance: defaultIfBlank, defaultIfEmpty, defaultString, difference, levenshteinDistance, countMatches

Install

npm install string-kit-js

Usage

const {
  isBlank,
  isNotBlank,
  isEmpty,
  isNotEmpty,
  equals,
  equalsIgnoreCase,
  contains,
  startsWith,
  endsWith,
  toUpper,
  toLower,
  capitalize,
  trim,
  trimToNull,
  trimToEmpty,
  repeat,
  reverse,
  countMatches,
  remove,
  leftPad,
  rightPad,
  substringBetween,
  normalizeSpace,
  swapCase,
  truncate,
  abbreviate,
  stripAccents,
  toCamelCase,
  toKebabCase,
  toSnakeCase,
  substringBeforeLast,
  substringAfterLast,
  ...
} = require("string-kit-js");

// ===== Check blank =====
console.log("isBlank(null)            ->", isBlank(null));       // true
console.log('isBlank("   ")           ->', isBlank("   "));      // true
console.log('isNotBlank("abc")        ->', isNotBlank("abc"));   // true

// ===== Empty check =====
console.log('isEmpty("")              ->', isEmpty(""));         // true
console.log('isNotEmpty("abc")        ->', isNotEmpty("abc"));   // true

// ===== Equals =====
console.log('equals("a", "a")         ->', equals("a", "a"));    // true
console.log('equalsIgnoreCase("abc", "ABC") ->', equalsIgnoreCase("abc", "ABC")); // true

// ===== String contains =====
console.log('contains("hello world", "world") ->', contains("hello world", "world")); // true
console.log('startsWith("hello", "he") ->', startsWith("hello", "he")); // true
console.log('endsWith("hello", "lo")   ->', endsWith("hello", "lo"));   // true

// ===== Transform =====
console.log('toUpper("hello")         ->', toUpper("hello"));    // "HELLO"
console.log('toLower("WORLD")         ->', toLower("WORLD"));    // "world"
console.log('capitalize("hello")      ->', capitalize("hello")); // "Hello"

// ===== Default value =====
console.log('defaultIfBlank("   ", "default")  ->', defaultIfBlank("   ", "default")); // "default"
console.log('defaultIfEmpty("", "fallback")    ->', defaultIfEmpty("", "fallback"));   // "fallback"

// ===== Substring helpers =====
console.log('substringBefore("abc:def", ":")   ->', substringBefore("abc:def", ":"));  // "abc"
console.log('substringAfter("abc:def", ":")    ->', substringAfter("abc:def", ":"));   // "def"

// ===== Trim helpers =====
console.log('trim("  abc  ")                  ->', trim("  abc  ")); // "abc"
console.log('trimToNull("   ")                ->', trimToNull("   ")); // null
console.log('trimToEmpty(null)                ->', trimToEmpty(null)); // ""

// ===== Other helpers =====
console.log('repeat("ab", 3)                  ->', repeat("ab", 3)); // "ababab"
console.log('reverse("hello")                 ->', reverse("hello")); // "olleh"
console.log('countMatches("one one one", "one") ->', countMatches("one one one", "one")); // 3
console.log('remove("a-b-c", "-")             ->', remove("a-b-c", "-")); // "abc"
console.log('leftPad("7", 3, "0")             ->', leftPad("7", 3, "0")); // "007"
console.log('rightPad("7", 3, "0")            ->', rightPad("7", 3, "0")); // "700"
console.log('substringBetween("[abc]", "[", "]") ->', substringBetween("[abc]", "[", "]")); // "abc"
console.log('substringBeforeLast("a/b/c", "/") ->', substringBeforeLast("a/b/c", "/")); // "a/b"
console.log('substringAfterLast("a/b/c", "/")  ->', substringAfterLast("a/b/c", "/")); // "c"

// ===== Normalize & case convert =====
console.log('normalizeSpace("  a   b  c  ")   ->', normalizeSpace("  a   b  c  ")); // "a b c"
console.log('swapCase("Hello JS")             ->', swapCase("Hello JS")); // "hELLO js"
console.log('truncate("Hello world", 8)       ->', truncate("Hello world", 8)); // "Hello..."
console.log('abbreviate("Hello world", 7)     ->', abbreviate("Hello world", 7)); // "Hell..."
console.log('stripAccents("Tôi yêu JS")       ->', stripAccents("Tôi yêu JS")); // "Toi yeu JS"
console.log('toCamelCase("hello world js")    ->', toCamelCase("hello world js")); // "helloWorldJs"
console.log('toKebabCase("HelloWorld JS")     ->', toKebabCase("HelloWorld JS")); // "hello-world-js"
console.log('toSnakeCase("HelloWorld JS")     ->', toSnakeCase("HelloWorld JS")); // "hello_world_js"