strfi

High-performance string utilities for JavaScript/TypeScript. Works everywhere: Node.js, browsers, Deno, Bun, and CLI tools.

Author

Sepehr Mohseni

• GitHub: @sepehr-mohseni
• LinkedIn: sepehr-mohseni
• npm: sepehr-mohseni

Installation

npm install strfi

Features

• Zero runtime dependencies
• Tree-shakeable (import only what you need)
• Full TypeScript support
• Works in Node.js, browsers, and edge runtimes
• Unicode-aware operations
• No eval() or dynamic code execution
• Minified bundle: ~22KB

Case Transformations

| Function | Description | Args | |----------|-------------|------| | toUpperCase | Converts to uppercase | str, options?: { locale } | | toLowerCase | Converts to lowercase | str, options?: { locale } | | capitalize | Capitalizes first character | str, options?: { locale } | | uncapitalize | Lowercases first character | str, options?: { locale } | | titleCase | Capitalizes first letter of each word | str, options?: { locale } | | camelCase | Converts to camelCase | str | | pascalCase | Converts to PascalCase | str | | snakeCase | Converts to snake_case | str | | kebabCase | Converts to kebab-case | str | | constantCase | Converts to CONSTANT_CASE | str | | dotCase | Converts to dot.case | str | | pathCase | Converts to path/case | str | | sentenceCase | Converts to Sentence case | str, options?: { locale } | | swapCase | Swaps uppercase/lowercase | str | | isUpperCase | Checks if all uppercase | str | | isLowerCase | Checks if all lowercase | str | | isTitleCase | Checks if title case | str |

Whitespace Operations

| Function | Description | Args | |----------|-------------|------| | trim | Removes whitespace from both ends | str | | trimStart | Removes whitespace from start | str | | trimEnd | Removes whitespace from end | str | | trimChars | Removes specific chars from both ends | str, chars | | trimCharsStart | Removes specific chars from start | str, chars | | trimCharsEnd | Removes specific chars from end | str, chars | | collapseWhitespace | Collapses multiple spaces to one | str | | removeWhitespace | Removes all whitespace | str | | padStart | Pads string at start | str, length, char? | | padEnd | Pads string at end | str, length, char? | | center | Centers string with padding | str, length, char? | | repeat | Repeats string n times | str, count | | insert | Inserts string at position | str, index, value | | removeAt | Removes chars at position | str, index, count? | | indent | Adds indentation to each line | str, spaces?, char? | | dedent | Removes common leading whitespace | str |

String Manipulation

| Function | Description | Args | |----------|-------------|------| | reverse | Reverses string (Unicode-safe) | str | | truncate | Truncates with ellipsis | str, options: { length, omission?, separator? } | | truncateMiddle | Truncates middle with ellipsis | str, options: { length, omission? } | | wordWrap | Wraps text at width | str, options: { width, indent?, cut? } | | slugify | Creates URL slug | str, options?: { separator?, lowercase?, strict? } | | between | Extracts string between delimiters | str, start, end | | betweenAll | Extracts all strings between delimiters | str, start, end | | remove | Removes all occurrences | str, search | | replaceFirst | Replaces first occurrence | str, search, replacement | | replaceLast | Replaces last occurrence | str, search, replacement | | replaceAll | Replaces all occurrences | str, search, replacement | | mask | Masks part of string | str, start, length?, char? | | shuffle | Randomly shuffles characters | str | | chunk | Splits into fixed-size chunks | str, size | | splitBy | Splits by multiple delimiters | str, delimiters | | join | Joins array with separator | arr, separator, lastSeparator? | | stripTags | Removes HTML/XML tags | str | | normalizeLineEndings | Normalizes line endings | str, ending? | | surround | Wraps with prefix/suffix | str, wrapper | | ensurePrefix | Adds prefix if missing | str, prefix | | ensureSuffix | Adds suffix if missing | str, suffix | | removePrefix | Removes prefix if present | str, prefix | | removeSuffix | Removes suffix if present | str, suffix | | lines | Splits into lines array | str | | first | Gets first n characters | str, n? | | last | Gets last n characters | str, n? |

String Validation

| Function | Description | Args | |----------|-------------|------| | isBlank | Checks if empty or whitespace only | str | | isNotBlank | Checks if has non-whitespace content | str | | isEmpty | Checks if string is empty | str | | isNotEmpty | Checks if string is not empty | str | | isAlpha | Checks if alphabetic only | str | | isAlphanumeric | Checks if alphanumeric only | str | | isNumeric | Checks if numeric only | str | | isInteger | Checks if valid integer string | str | | isDecimal | Checks if valid decimal string | str | | isAscii | Checks if ASCII characters only | str | | isPrintableAscii | Checks if printable ASCII only | str | | isHexadecimal | Checks if valid hex string | str | | isUUID | Checks if valid UUID format | str | | isEmail | Checks if valid email format | str | | isURL | Checks if valid URL | str | | isJSON | Checks if valid JSON string | str | | isIPv4 | Checks if valid IPv4 address | str | | isIPv6 | Checks if valid IPv6 address | str | | isCreditCard | Validates credit card (Luhn) | str | | isSlug | Checks if valid URL slug | str | | startsWith | Checks if starts with substring | str, search, position? | | endsWith | Checks if ends with substring | str, search, position? | | contains | Checks if contains substring | str, search, position? | | containsAll | Checks if contains all substrings | str, searches | | containsAny | Checks if contains any substring | str, searches | | matches | Checks if matches regex | str, pattern | | compare | Compares two strings | str1, str2, options?: { locale } | | equals | Checks strict equality | str1, str2 | | equalsIgnoreCase | Checks equality ignoring case | str1, str2 | | isPalindrome | Checks if palindrome | str | | isWhitespace | Checks if whitespace only | str | | hasUpperCase | Checks if has uppercase | str | | hasLowerCase | Checks if has lowercase | str | | hasDigits | Checks if has digits | str | | hasSpecialChars | Checks if has special characters | str |

Encoding & Escaping

| Function | Description | Args | |----------|-------------|------| | escapeHtml | Escapes HTML entities | str | | unescapeHtml | Unescapes HTML entities | str | | escapeXml | Escapes XML entities | str | | unescapeXml | Unescapes XML entities | str | | escapeRegex | Escapes regex special chars | str | | escapeSqlLike | Escapes SQL LIKE wildcards | str, escapeChar? | | escapeShell | Escapes for shell commands | str | | toBase64 | Encodes to Base64 | str | | fromBase64 | Decodes from Base64 | str | | toBase64Url | Encodes to URL-safe Base64 | str | | fromBase64Url | Decodes URL-safe Base64 | str | | encodeUrl | URL encodes string | str | | decodeUrl | URL decodes string | str | | toHex | Converts to hex string | str | | fromHex | Converts from hex string | str | | toAsciiCodes | Gets ASCII codes array | str | | fromAsciiCodes | Creates string from ASCII codes | codes | | rot13 | Applies ROT13 cipher | str |

Search & Analysis

| Function | Description | Args | |----------|-------------|------| | countOccurrences | Counts substring occurrences | str, search, overlap? | | countWords | Counts words | str | | countLines | Counts lines | str | | countSentences | Counts sentences | str | | countParagraphs | Counts paragraphs | str | | charFrequency | Gets character frequency map | str | | wordFrequency | Gets word frequency map | str | | indicesOf | Gets all indices of substring | str, search | | nthIndexOf | Gets nth index of substring | str, search, n | | extractNumbers | Extracts all numbers | str | | extractWords | Extracts all words | str | | extractEmails | Extracts email addresses | str | | extractUrls | Extracts URLs | str | | extractHashtags | Extracts hashtags | str | | extractMentions | Extracts @mentions | str | | levenshteinDistance | Calculates edit distance | str1, str2 | | similarity | Calculates similarity (0-1) | str1, str2 | | longestCommonSubstring | Finds longest common substring | str1, str2 | | longestCommonPrefix | Finds common prefix | strings[] | | longestCommonSuffix | Finds common suffix | strings[] |

Unicode & i18n

| Function | Description | Args | |----------|-------------|------| | normalize | Normalizes Unicode form | str, form? | | removeDiacritics | Removes accents/diacritics | str | | toCodePoints | Gets Unicode code points | str | | fromCodePoints | Creates string from code points | codePoints | | graphemeLength | Gets grapheme cluster count | str | | toGraphemes | Splits into grapheme clusters | str | | toWords | Splits into words (locale-aware) | str, locale? | | isLetter | Checks if Unicode letter | char, locale? | | isDigit | Checks if Unicode digit | char | | isSpace | Checks if Unicode space | char | | isPunctuation | Checks if Unicode punctuation | char | | isRTL | Checks if right-to-left text | str | | isLTR | Checks if left-to-right text | str | | getDirection | Gets text direction (ltr/rtl/neutral) | str | | formatNumber | Formats number for locale | num, locale?, options? | | formatDate | Formats date for locale | date, locale?, options? | | formatCurrency | Formats currency for locale | amount, currency, locale? | | formatRelativeTime | Formats relative time | value, unit, locale? | | pluralize | Selects plural form | count, forms, locale? | | collate | Sorts strings (locale-aware) | strings, locale?, options? | | getLocaleDisplayName | Gets locale display name | locale, displayLocale? | | getRegionDisplayName | Gets region display name | region, displayLocale? |

Formatting

| Function | Description | Args | |----------|-------------|------| | template | Interpolates template string | str, values, options? | | format | Formats with positional args | str, ...args | | formatNamed | Formats with named args | str, values | | sprintf | C-style sprintf | format, ...args | | zeroPad | Pads number with zeros | num, length | | formatThousands | Adds thousand separators | num, separator? | | formatBytes | Formats bytes (KB, MB, etc.) | bytes, decimals? | | formatDuration | Formats duration in seconds | seconds | | ordinal | Creates ordinal (1st, 2nd, etc.) | num | | loremIpsum | Generates lorem ipsum text | words | | randomString | Generates random string | length, options? | | uuid | Generates UUID v4 | none | | hashCode | Generates hash code | str |

Platform Support

| Platform | Supported | |----------|-----------| | Node.js 16+ | ✅ | | Chrome/Edge | ✅ | | Firefox | ✅ | | Safari | ✅ | | Deno | ✅ | | Bun | ✅ | | React Native | ✅ | | Cloudflare Workers | ✅ |

Usage

ESM (Browser/Node.js)

import { slugify, escapeHtml } from 'strfi';

CommonJS (Node.js)

const { slugify, escapeHtml } = require('strfi');

CLI Scripts

#!/usr/bin/env node
import { slugify } from 'strfi';
console.log(slugify(process.argv[2]));

License

MIT © Sepehr Mohseni