build: Use promises in algolia script

bin/sync-algolia.js

@@ -21,23 +21,53 @@ function syncAlgolia() {
   const index = client.initIndex('icons');
   const indexTmp = client.initIndex('icons_tmp');
 
-  indexTmp.setSettings({
-    searchableAttributes: ['unordered(name)', 'unordered(tags)'],
-    customRanking: ['asc(name)'],
-  });
+  console.log(
+    "Copying target index's settings, synonyms and rules into temporary index...",
+  );
+  scopedCopyIndex(client, index.indexName, indexTmp.indexName)
+    .then(() => {
+      const objects = Object.keys(icons).map(name => ({
+        name,
+        tags: tags[name] || [],
+      }));
 
-  const records = Object.keys(icons).map(name => ({
-    name,
-    tags: tags[name] || [],
-  }));
+      console.log('Adding objects to the temporary index...');
+      return addObjects(indexTmp, objects);
+    })
+    .then(() => {
+      console.log('Moving temporary index to target index...');
+      return moveIndex(client, indexTmp.indexName, index.indexName);
+    });
+}
 
-  console.log('Pushing data to the temporary index...');
-  indexTmp.addObjects(records, err => {
-    if (err) throw err;
+function scopedCopyIndex(
+  client,
+  indexNameSrc,
+  indexNameDest,
+  scope = ['settings', 'synonyms', 'rules'],
+) {
+  return new Promise((resolve, reject) => {
+    client.copyIndex(indexNameSrc, indexNameDest, scope, (error, contents) => {
+      if (error) reject(error);
+      resolve(contents);
+    });
   });
+}
+
+function addObjects(index, objects) {
+  return new Promise((resolve, reject) => {
+    index.addObjects(objects, (error, contents) => {
+      if (error) reject(error);
+      resolve(contents);
+    });
+  });
+}
 
-  console.log('Moving temporary index to target index...');
-  client.moveIndex(indexTmp.indexName, index.indexName, err => {
-    if (err) throw err;
+function moveIndex(client, indexNameSrc, indexNameDest) {
+  return new Promise((resolve, reject) => {
+    client.moveIndex(indexNameSrc, indexNameDest, (error, contents) => {
+      if (error) reject(error);
+      resolve(contents);
+    });
   });
 }