BookStack/resources/js/services/components.js

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/**
* A mapping of active components keyed by name, with values being arrays of component
* instances since there can be multiple components of the same type.
* @type {Object<String, Component[]>}
*/
const components = {};
/**
* A mapping of component class models, keyed by name.
* @type {Object<String, Constructor<Component>>}
*/
const componentModelMap = {};
/**
* A mapping of active component maps, keyed by the element components are assigned to.
* @type {WeakMap<Element, Object<String, Component>>}
*/
const elementComponentMap = new WeakMap();
/**
* Initialize a component instance on the given dom element.
* @param {String} name
* @param {Element} element
*/
function initComponent(name, element) {
/** @type {Function<Component>|undefined} **/
const componentModel = componentModelMap[name];
if (componentModel === undefined) return;
// Create our component instance
/** @type {Component} **/
let instance;
try {
instance = new componentModel();
instance.$name = name;
instance.$el = element;
const allRefs = parseRefs(name, element);
instance.$refs = allRefs.refs;
instance.$manyRefs = allRefs.manyRefs;
instance.$opts = parseOpts(name, element);
instance.setup();
} catch (e) {
console.error('Failed to create component', e, name, element);
}
// Add to global listing
if (typeof components[name] === "undefined") {
components[name] = [];
}
components[name].push(instance);
// Add to element mapping
const elComponents = elementComponentMap.get(element) || {};
elComponents[name] = instance;
elementComponentMap.set(element, elComponents);
}
/**
* Parse out the element references within the given element
* for the given component name.
* @param {String} name
* @param {Element} element
*/
function parseRefs(name, element) {
const refs = {};
const manyRefs = {};
const prefix = `${name}@`
const selector = `[refs*="${prefix}"]`;
const refElems = [...element.querySelectorAll(selector)];
if (element.matches(selector)) {
refElems.push(element);
}
for (const el of refElems) {
const refNames = el.getAttribute('refs')
.split(' ')
.filter(str => str.startsWith(prefix))
.map(str => str.replace(prefix, ''))
.map(kebabToCamel);
for (const ref of refNames) {
refs[ref] = el;
if (typeof manyRefs[ref] === 'undefined') {
manyRefs[ref] = [];
}
manyRefs[ref].push(el);
}
}
return {refs, manyRefs};
}
/**
* Parse out the element component options.
* @param {String} name
* @param {Element} element
* @return {Object<String, String>}
*/
function parseOpts(name, element) {
const opts = {};
const prefix = `option:${name}:`;
for (const {name, value} of element.attributes) {
if (name.startsWith(prefix)) {
const optName = name.replace(prefix, '');
opts[kebabToCamel(optName)] = value || '';
}
}
return opts;
}
/**
* Convert a kebab-case string to camelCase
* @param {String} kebab
* @returns {string}
*/
function kebabToCamel(kebab) {
const ucFirst = (word) => word.slice(0,1).toUpperCase() + word.slice(1);
const words = kebab.split('-');
return words[0] + words.slice(1).map(ucFirst).join('');
}
/**
* Initialize all components found within the given element.
* @param {Element|Document} parentElement
*/
export function init(parentElement = document) {
const componentElems = parentElement.querySelectorAll(`[component],[components]`);
for (const el of componentElems) {
const componentNames = `${el.getAttribute('component') || ''} ${(el.getAttribute('components'))}`.toLowerCase().split(' ').filter(Boolean);
for (const name of componentNames) {
initComponent(name, el);
}
}
}
/**
* Register the given component mapping into the component system.
* @param {Object<String, ObjectConstructor<Component>>} mapping
*/
export function register(mapping) {
const keys = Object.keys(mapping);
for (const key of keys) {
componentModelMap[camelToKebab(key)] = mapping[key];
}
}
/**
* Get the first component of the given name.
* @param {String} name
* @returns {Component|null}
*/
export function first(name) {
return (components[name] || [null])[0];
}
/**
* Get all the components of the given name.
* @param {String} name
* @returns {Component[]}
*/
export function get(name) {
return components[name] || [];
}
/**
* Get the first component, of the given name, that's assigned to the given element.
* @param {Element} element
* @param {String} name
* @returns {Component|null}
*/
export function firstOnElement(element, name) {
const elComponents = elementComponentMap.get(element) || {};
return elComponents[name] || null;
}
function camelToKebab(camelStr) {
return camelStr.replace(/[A-Z]/g, (str, offset) => (offset > 0 ? '-' : '') + str.toLowerCase());
}