string-format-helpers

Lightweight string formatting helpers: casing conversions, slugify, template formatting, truncate, padding, and more. Zero-dependency, ESM-only.

Features

• Casing: camelCase, PascalCase, snake_case, kebab-case, Title Case
• Slugify and humanize
• Safe trimming and ASCII normalization (remove diacritics)
• Templating: format("Hello {name}", { name: "Tomas" })
• Truncate (by characters or words) and pad (left/right/both)
• Strip HTML tags
• Sorting helpers: compare, stableSort, orderBy (multi-criteria)
• Pivoting helpers: groupBy, keyBy, transpose (2D array), pivotTable (rows x cols aggregation)
• Hash/object helpers: createHash, setIn/updateIn/deleteIn (immutable by default), merge (deep/shallow)
• Tree helpers: buildTree (from id/parentId), walkTree (traverse), findInTree, mapTree (immutable)

Installation

• Using npm: npm install string-format-helpers

• Using yarn: yarn add string-format-helpers

• Using pnpm: pnpm add string-format-helpers

Usage

ESM import (Node.js >=14 or any bundler):

import sf, { camelCase, titleCase, format, slugify, pad, truncate } from 'string-format-helpers';

console.log(camelCase('Hello world')); // 'helloWorld' console.log(titleCase('hello world')); // 'Hello World' console.log(slugify('Crème brûlée!')); // 'creme-brulee' console.log(format('Hello, {name}!', { name: 'Tomas' })); // 'Hello, Tomas!' console.log(truncate('This is a long sentence', 12)); // 'This is a …' console.log(pad('42', 5, '0', 'left')); // '00042'

// Or use the default export console.log(sf.kebabCase('Hello World')); // 'hello-world'

API

All functions are pure and return strings unless noted.

• toAscii(input) Normalize a string to ASCII by removing diacritics.

• safeTrim(input) Trim safely; null/undefined become empty string.

• capitalize(input) Uppercase the first character.

• titleCase(input) Capitalize the first letter of each word.

• camelCase(input) Convert to lower camelCase.

• pascalCase(input) Convert to PascalCase.

• snakeCase(input) Convert to snake_case.

• kebabCase(input) Convert to kebab-case.

• slugify(input) URL-friendly lowercase slug.

• humanize(input) Convert technical strings to friendly words.

• truncate(input, maxLength = 100, options) Truncate by characters (default) or words (options.byWords = true). Options: { omission = '…', byWords = false }.

• pad(input, length, char = ' ', direction = 'right') Pad string to length. direction: 'left' | 'right' | 'both'.

• stripTags(input) Remove HTML tags.

• format(template, params) Simple templating with {placeholders}.

Hash/object helpers

• createHash(entries | obj) Create a plain object from [key, value] entries or clone an existing object.

• setIn(obj, path, value, options) Set a nested value by path (array or dot string). Immutable by default. Example: const obj = { a: { b: 1 } }; const next = setIn(obj, 'a.c', 2); // { a: { b: 1, c: 2 } }

• updateIn(obj, path, updater, options) Update a nested value using an updater: (current) => next.

• deleteIn(obj, path, options) Delete a nested key. Immutable by default.

• merge(target, ...sources, options) Deep merge plain objects. Arrays: replace (default) or concat.

Tree helpers

• buildTree(list, { id='id', parentId='parentId', children='children', rootParent=null }) Build a forest (array of roots) from a flat list with id/parentId.

• walkTree(nodes, visitor, { childrenKey='children', order='pre'|'post' }) Traverse nodes and call visitor(node, context).

• findInTree(nodes, predicate) Return first node matching predicate.

• mapTree(nodes, mapper) Create a new tree by mapping each node (immutable).

TypeScript

The package is JS-only but is compatible with TypeScript via type inference on usage. If you need types, you can add a community .d.ts later.

Package structure

• src/index.js — ESM module with named and default exports
• package.json — ESM config, exports, publish settings
• README.md — documentation
• LICENSE — MIT

Development

• Quick test to ensure the module loads: npm test

• Try functions in Node REPL: node

  import * as sf from './src/index.js'; sf.camelCase('hello world');

Publishing (npm)

1. Ensure you are logged in: npm login

2. Update version per semver: npm version patch # or minor / major

3. Publish the package: npm publish --access public

Notes:

• The package is ESM-only ("type": "module").
• The publishConfig is set for public publishing. For scoped packages (e.g., @your-scope/pkg), keep --access public.

License

MIT © Contributors

Troubleshooting: "Set the BROWSER environment variable to your desired browser" (npm error)

This message usually comes from tools that try to open your default browser (for example, react-scripts start in Create React App). This library itself does not open a browser, but if you see this error while working in the same environment, set the BROWSER environment variable explicitly.

Common values:

• chrome
• firefox
• edge
• none (disables auto-opening the browser)

Quick, temporary settings (one-off):

• macOS/Linux (Bash, Zsh):
  • Open a specific browser: BROWSER=chrome npm start
  • Disable opening a browser: BROWSER=none npm start
• Windows PowerShell:
  • Open a specific browser:
    • $env:BROWSER = "chrome"
    • npm start
  • Disable opening a browser:
    • $env:BROWSER = "none"
    • npm start
• Windows cmd.exe:
  • Open a specific browser: set BROWSER=chrome && npm start
  • Disable opening a browser: set BROWSER=none && npm start

Set permanently (so you don't have to set it every time):

• Windows PowerShell (current user):
  • [Environment]::SetEnvironmentVariable("BROWSER", "chrome", "User")
• Windows cmd.exe (current user):
  • setx BROWSER chrome
• macOS/Linux (Bash):
  • echo 'export BROWSER=chrome' >> ~/.bashrc && source ~/.bashrc
• macOS/Linux (Zsh):
  • echo 'export BROWSER=chrome' >> ~/.zshrc && source ~/.zshrc

Notes:

• Use BROWSER=none if you prefer no browser to be opened automatically.
• If you're operating inside WSL and want to launch the Windows browser, ensure wslview is installed or set BROWSER to a Windows browser executable available on PATH (e.g., "/mnt/c/Program Files/Google/Chrome/Application/chrome.exe").