Merge pull request #3774 from overleaf/jpa-meta

[frontend] import meta tag processing from das7pads fork

GitOrigin-RevId: ca74ff9fbbcb51091a626a45468ff3d24d6136ca

services/web/frontend/js/utils/meta.js

@@ -0,0 +1,48 @@
+import _ from 'lodash'
+
+// cache for parsed values
+const cache = new Map()
+
+export default function getMeta(name, fallback) {
+  if (cache.has(name)) return cache.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
+  }
+  cache.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 'sharelatex' before 'sharelatex.templates'
+    .sort()
+    .forEach(nameWithNamespace => {
+      const label = nameWithNamespace.slice('ol-'.length)
+      _.set(window, label, getMeta(nameWithNamespace))
+      _.set(window.data, label, getMeta(nameWithNamespace))
+    })
+}
+convertMetaToWindowAttributes()