import _ from 'lodash' // cache for parsed values window.metaAttributesCache = window.metaAttributesCache || new Map() export default function getMeta(name, fallback) { if (window.metaAttributesCache.has(name)) { return window.metaAttributesCache.get(name) } const element = document.head.querySelector(`meta[name="${name}"]`) if (!element) { return fallback } const plainTextValue = element.content let value switch (element.dataset.type) { case 'boolean': // in pug: content=false -> no content field // in pug: content=true -> empty content field value = element.hasAttribute('content') break case 'json': if (!plainTextValue) { // JSON.parse('') throws value = undefined } else { value = JSON.parse(plainTextValue) } break default: value = plainTextValue } window.metaAttributesCache.set(name, value) return value } function convertMetaToWindowAttributes() { window.data = window.data || {} Array.from(document.querySelectorAll('meta[name^="ol-"]')) .map(element => element.name) // process short labels before long ones: // e.g. assign 'foo' before 'foo.bar' .sort() .forEach(nameWithNamespace => { const label = nameWithNamespace.slice('ol-'.length) _.set(window, label, getMeta(nameWithNamespace)) _.set(window.data, label, getMeta(nameWithNamespace)) }) } convertMetaToWindowAttributes()