feat: attr keys can have array values (resolves #231)

src/client/updaters/attribute.js

@@ -1,3 +1,5 @@
+import isArray from '../../shared/isArray'
+
 /**
  * Updates the document's html tag attributes
  *
@@ -12,8 +14,9 @@ export default function updateAttribute({ attribute } = {}, attrs, tag) {
   const keepIndexes = []
   for (const attr in attrs) {
     if (attrs.hasOwnProperty(attr)) {
-      const value = attrs[attr] || ''
-      tag.setAttribute(attr, value)
+      const value = isArray(attrs[attr]) ? attrs[attr].join(' ') : attrs[attr]
+
+      tag.setAttribute(attr, value || '')
 
       if (!vueMetaAttrs.includes(attr)) {
         vueMetaAttrs.push(attr)

src/server/generators/attribute.js

@@ -1,5 +1,6 @@
 import { booleanHtmlAttributes } from '../../shared/constants'
 import { isUndefined } from '../../shared/typeof'
+import isArray from '../../shared/isArray'
 
 /**
  * Generates tag attributes for use on the server.
@@ -20,7 +21,7 @@ export default function attributeGenerator({ attribute } = {}, type, data) {
 
           attributeStr += isUndefined(data[attr]) || booleanHtmlAttributes.includes(attr)
             ? attr
-            : `${attr}="${data[attr]}"`
+            : `${attr}="${isArray(data[attr]) ? data[attr].join(' ') : data[attr]}"`
 
           attributeStr += ' '
         }

src/shared/escape.js

@@ -35,7 +35,11 @@ export default function escape(info, { tagIDKeyName }, escapeSequences = []) {
     if (isString(value)) {
       escaped[key] = escapeSequences.reduce((val, [v, r]) => val.replace(v, r), value)
     } else if (isArray(value)) {
-      escaped[key] = value.map(v => escape(v, { tagIDKeyName }, escapeSequences))
+      escaped[key] = value.map((v) => {
+        return isObject(v)
+          ? escape(v, { tagIDKeyName }, escapeSequences)
+          : escapeSequences.reduce((val, [v, r]) => val.replace(v, r), v)
+      })
     } else if (isObject(value)) {
       escaped[key] = escape(value, { tagIDKeyName }, escapeSequences)
     } else {