A collection of small utility functions I have written over the years. Will receive updates.

bits.js

/* Table Of Contents:
GeneratorFunction
	The GeneratorFunction constructor, exposed.
isSetIterator
	Returns true if the object is a bultin Set Iterator.
isMapIterator
	Returns true if the object is a builtin Map Iterator.
iterableObject
	Make a regular Object an iterable.
get
	Sends an HTTP GET request to `url` with response type `type`.
head
	Sends an HTTP HEAD request to `url`.
xhrException
	Throws an error if the fetch request fails.
getHash
	Returns the value of the URL hash parameter, or `null` if the value is empty.
scrollToHeading
	Scrolls to the first Heading element which matches `title`.
scrollToHash
	Scrolls to the first Heading element which matches the URL hash parameter.
loadScript
	Dynamically loads a JavaScript script from a URL.
loadStyle
	Dynamically loads a CSS Stylesheet from a URL.
createQueryString
	Returns a URL Query String using the key/value pairs in `obj`.
setQueryString
	Sets the URL Query String using the key/value pairs in `obj`.
getQueryString
	Returns an object containing the URL Query String parameters, or `null` if there is none.
empty
	Removes all child Nodes from a DOM Element.
newFragmentClone
	Clones the child nodes of an element into a new Document Fragment.
newFragmentParse
	Parses an HTML tagString into DOM nodes in a Document Fragment.
compose
	Returns a new Function composed from an Array of Functions.
plotPath
	(NodeJS fs module) Traverses a filesystem path, creating it along the way.
*/

// The GeneratorFunction constructor, exposed
const GeneratorFunction = (function* () { }).constructor;

// Returns true if the object is a bultin Set Iterator
const setIteratorProto = (new Set())[Symbol.iterator]().__proto__;
const isSetIterator = obj => obj.__proto__ === setIteratorProto;
// Returns true if the object is a builtin Map Iterator
const mapIteratorProto = (new Map())[Symbol.iterator]().__proto__;
const isMapIterator = obj => obj.__proto__ === mapIteratorProto;

// Make a regular Object an iterable
function IterableObject(obj) {
	obj[Symbol.iterator] = this.wrapper;
	return obj;
};
IterableObject.prototype.wrapper = function* () {
	for (const prop of Object.keys(this)) yield this[prop];
};

// Sends an HTTP GET request to `url` with response type `type`.
function get(url = "/", type = "text") {
	return fetch(url).then(xhrException).then(res => res[type]());
}
// Sends an HTTP HEAD request to `url`.
function head(url = "/") {
	return fetch(url, { method: "HEAD" }).then(xhrException).then(res => res.headers);
}
// Throws an error if the fetch request fails.
function xhrException(res) {
	if (!res.ok) throw new Error(res.statusText);
	return res;
}

// Returns the value of the URL hash parameter, or `null` if the value is empty.
function getHash() {
	if (window.location.hash.length < 2) return null;
	return window.location.hash.slice(1, window.location.hash.length)
}

// Scrolls to the first Heading element which matches `title`.
const headingSelector = "h1, h2, h3, h4, h5, h6";
function scrollToHeading(title) {
	const headings = document.querySelectorAll(headingSelector);
	if (headings === null || headings.length === 0) return;
	for (const heading of headings) {
		const headingTitle = heading.textContent;
		if (headingTitle.length === 0) continue;
		if (headingTitle.trim() === title) heading.scrollIntoView();
	}
}

// Scrolls to the first Heading element which matches the URL hash parameter.
function scrollToHash() {
	const title = getHash();
	if (title === null) return;
	scrollToHeading(title);
}

// Dynamically loads a JavaScript script from a URL.
function loadScript(url) {
	return new Promise(resolve => {
		const script = document.createElement("script");
		script.src = url;
		script.type = "application/javascript";
		script.addEventListener("load", _=> resolve());
		document.head.appendChild(script);
	});
}

// Dynamically loads a CSS Stylesheet from a URL.
function loadStyle(url) {
	const link = document.createElement("link");
	link.href = url;
	link.type = "text/css";
	link.rel = "stylesheet";
	document.head.appendChild(link);
}

// Returns a URL Query String using the key/value pairs in `obj`.
function createQueryString(obj) {
	var queryString = "";
	for (const prop in obj) queryString += `${queryString.length > 1 ? "&" : "?"}${prop}${obj[prop] !== "" ? "=" + obj[prop] : ""}`;
	return encodeURI(queryString);
}

// Sets the URL Query String using the key/value pairs in `obj`. Uses getQueryString from below.
function setQueryString(obj) {
	const loc = window.location;
	const url = `${loc.protocol}//${loc.host}${loc.pathname}${createQueryString(obj)}`;
	history.pushState({ path: url }, "", url);
}

// Returns an object containing the URL Query String parameters, or `null` if there is none.
function getQueryString() {
	if (window.location.search.length === 0) return null;
	const paramsObj = {};
	Array.from(new URLSearchParams(window.location.search).entries()).forEach(pair => paramsObj[pair[0]] = pair[1]);
	return paramsObj;
}

// Removes all child Nodes from a DOM Element.
function empty(element) {
	while (element.hasChildNodes()) element.removeChild(element.lastChild);
}

/// Clones the child nodes of an element into a new Document Fragment.
function newFragmentClone(sourceElem) {
	const frag = document.createDocumentFragment();
	for (var node of sourceElem.childNodes.values()) {
		frag.appendChild(node.cloneNode(true));
	}
	return frag;
}

// Parses an HTML tagString into DOM nodes in a Document Fragment.
function newFragmentParse(tagString) {
	return document.createRange().createContextualFragment(tagString);
}

// Returns a new Function composed from an Array of Functions.
function compose(...functions) {
	return function(value) {
		for (const curFunc of functions) value = curFunc(value);
		return value;
	}
}

// (NodeJS fs module) Traverses a filesystem path, creating it along the way.
function plotPath(path) {
	path = path.split("/");
	path.pop();
	var curPath = path.shift();
	for (const node of path) {
		curPath = curPath + "/" + node;
		try {
			fs.statSync(curPath);
		} catch (error) {
			if (error.code === "ENOENT") fs.mkdirSync(curPath);
			else throw error;
		}
	}
}