core/adapter: use findIndex() (#8791)

Replace `.map(...).indexOf(...)` with `.findIndex(...)`.

Author: alxndrsn

packages/node_modules/pouchdb-core/src/adapter.js

@@ -598,8 +598,7 @@ class AbstractPouchDB extends EventEmitter {
 
           for (var i = 0; i < paths.length; i++) {
             var currentPath = paths[i];
-            var hashIndex = currentPath.ids.map(function (x) { return x.id; })
-              .indexOf(revHash);
+            const hashIndex = currentPath.ids.findIndex(x => x.id === revHash);
             var hashFoundAtRevPos = hashIndex === (revNo - 1);
 
             if (hashFoundAtRevPos || (!path && hashIndex !== -1)) {
@@ -614,8 +613,8 @@ class AbstractPouchDB extends EventEmitter {
             return cb(err);
           }
 
-          var indexOfRev = path.ids.map(function (x) { return x.id; })
-            .indexOf(doc._rev.split('-')[1]) + 1;
+          const pathId = doc._rev.split('-')[1];
+          const indexOfRev = path.ids.findIndex(x => x.id === pathId) + 1;
           var howMany = path.ids.length - indexOfRev;
           path.ids.splice(indexOfRev, howMany);
           path.ids.reverse();