hofkit

hofkit (Higher Order Function toolKIT) is a modular functional utility library for JavaScript & TypeScript. This library collects frequently rewritten experimental functional wrappers for commonly used utility functions (either custom or from popular libraries such as lodash). These wrappers emphasised functional concepts (e.g., higher order functions, state purity, etc.) to provide functional benefits (e.g., less state, composition) whilst preserving compatibility with existing imperative approaches.

Through this flexiblity, the toolkit aims to be reusable across projects for a wide variety of uses ranging from array & object manipulation (e.g., filtering object entries) to concurrency-controlled Promises.

Additional benefits include builtin type support, environment-specific modules (i.e., featureGroups that group functions to separate dependencies), live-reloadable per-function test suites, and auto-generated live-reloadable documentation.

Features

|Feature|Details| |-|-| |Provide a library of functional utility functions|Includes 164 core functions & 14 node-environment functions (as of initial release), that cover a variety of uses ranging from array & object manipulation (e.g., filtering object entries) to concurrency-controlled Promises |Compatible with function & imperative approaches|Provides functional benefits (e.g., purity, composition) whilst remaining compatibility with imperative implementations| |Interoperable with JavaScript & TypeScript|-| |Builtin TypeScript support for all functions|All functions are written in TypeScript to generate bundled environment-specific declaration files| |Typed return values for functional composition|-| |Auto-generated live-reloadable documentation|Documentation is generated & live-reloadable for all featureGroup functions, which includes type signatures & any manual documentation| |Modular environment-specific functions|Environment-specific functions are grouped into individually importable featureGroup modules (e.g., core, node, etc.) to separate dependencies| |Environment-specific per-function unit test suites|All functions are easily testable via dedicated environment grouped live-reloadable test suites (totalling 180 test suites & 614 tests as of initial release) |Supports testing curried functions via command line|See test:cli in Scripts |Consistent code via JavaScript & TypeScript linting|Uses eslint-config-jsx to ensure consistent code

Usage

Install:

npm install hofkit

Using core functions in TypeScript:

import * as H from 'hofkit'; // Import all `core` functions.
// JavaScript: const H = require('hofkit');

import { titleCase } from H; // Named import.
// JavaScript: const { titleCase } = H;

titleCase('foo bar'); //=> 'Foo Bar'

// Typed return value: `toTitle: any => string`.
const toTitle = H.compose(
    titleCase,
    H.trim,
);
toTitle(' Foo-barBaz '); //=> 'Foo Bar Baz'

Using modular environment-specific functions (currently only node is supported), e.g., node functions:

import * as H from 'hofkit';
import * as HN from 'hofkit/dist/node'; // Import all `node` functions (requires Node environment).
import { readFile } from HN; // Named import.

// Using `async` IFFE for clarity but can be replaced by `H.promiseTryOr` to handle errors.
(async () => {
    // Writing to a file.
    await HN.writeFile('path/to/file')('foo');

    // Find existing paths.
    const filePaths = ['path1', 'path2', 'path3']; // Several file paths.
    const existingFilePaths = await H.promiseFilter(HN.pathExists);

    // Reading data for all existing files.
    let contents: string[] = [];
    const poolSize = 10;
    const onPoolComplete = (poolData: string) => [...contents, ...poolData]; // Flattens data from pools.
    const toFileContents = H.compose(
        H.promiseAll(poolSize, onPoolComplete), // Controlled concurrency.
        H.map(readFile)
    );
    toFileContents(existingFilePaths); //=> [['content1', ...], ...]

    // Overwriting all files.
    const writeFoo = (filePath: string) => HN.writeFile(filePath)('foo');
    const overwriteExistingFiles = H.compose(
        H.promiseAll(), // Uncontrolled concurrency;
        H.map(HN.writeFoo)
    );
    overwriteExistingFiles(filePaths);
})();

Documentation

Function documentation is available via the documentation website.

Screenshot of core documentation website:

Scripts

|Script|Info| |-|-| |test|Run all tests| |test:core|Run all core feature group tests| |test:node|Run all node feature group tests| |test <...test-names>|Run tests matching test-names| |test:watch|Run all tests in watch mode| |test:cli <functionName> <...argSets>|Runs a function matching functionName with argSets (see runFunctionFromCli.ts)| |test:data:reset|Resets the test data directory (i.e., _testDataDir/) & its contents| |docs:clean|Remove existing docs| |docs:build|Output documentation to docs/| |docs:build:serve|Output & serve docs| |docs:serve|Serve existing docs in watch mode| |docs:serve:open|Open served docs| |docs:watch|Output docs in watch mode| |docs:watch:serve|Output & serve docs in watch mode| |build:clean|Removes the generated dist/ directory| |build:featureGroupIndexes|Updates all feature group index.ts files (i.e., updates exported functions, see updateFeatureGroupIndexes.ts)| |build|Generates the production dist/ directory & its contents (minified bundles, bundled declarations, etc.)| |build:dev|Development alternative to build| |pack:clean|Removes generated tarball files| |pack|Runs pack:clean before re-generating a tarball file containing npm required (e.g., package.json) & generated files (i.e., _dist/| |pack:dry|Same as pack but prints tarball file contents without generating the tarball file| |deploy:pre|Runs all pre-deploy scripts (e.g., test, build, pack, etc.)| |deploy:major|Runs deploy:pre before publishing an incremented major version| |deploy:minor|Runs deploy:pre before publishing an incremented minor version| |deploy:patch|Runs deploy:pre before publishing an incremented patch version| |deploy|Runs deploy:pre before publishing the current version|

Future Plans

• Complete remaining spec functions
• Test async composition
• Support web environments (e.g., browser, react, etc.)
• Changelog