chore(abstract-mapreduce): refactor to for ... of loops (#8892)

refactor to for ... of loops

Author: SourceR85

packages/node_modules/pouchdb-abstract-mapreduce/src/index.js

@@ -136,16 +136,16 @@ function createAbstractMapReduce(localDocName, mapper, reducer, ddocValidator) {
   }
 
   function readAttachmentsAsBlobOrBuffer(res) {
-    res.rows.forEach(function (row) {
+    for (const row of res.rows) {
       const atts = row.doc && row.doc._attachments;
       if (!atts) {
-        return;
+        continue;
       }
-      Object.keys(atts).forEach(function (filename) {
+      for (const filename of Object.keys(atts)) {
         const att = atts[filename];
         atts[filename].data = b64ToBluffer(att.data, att.content_type);
-      });
-    });
+      }
+    }
   }
 
   function postprocessAttachments(opts) {
@@ -216,12 +216,12 @@ function createAbstractMapReduce(localDocName, mapper, reducer, ddocValidator) {
           '{group: true}');
       }
     }
-    ['group_level', 'limit', 'skip'].forEach(function (optionName) {
+    for (const optionName of ['group_level', 'limit', 'skip']) {
       const error = checkPositiveInteger(options[optionName]);
       if (error) {
         throw error;
       }
-    });
+    }
   }
 
   async function httpQuery(db, fun, opts) {
@@ -298,12 +298,12 @@ function createAbstractMapReduce(localDocName, mapper, reducer, ddocValidator) {
       }
 
       // fail the entire request if the result contains an error
-      result.rows.forEach(function (row) {
+      for (const row of result.rows) {
         /* istanbul ignore if */
         if (row.value && row.value.error && row.value.error === "builtin_reduce_error") {
           throw new Error(row.reason);
         }
-      });
+      }
 
       return new Promise(function (resolve) {
         resolve(result);
@@ -312,13 +312,13 @@ function createAbstractMapReduce(localDocName, mapper, reducer, ddocValidator) {
 
     // We are using a temporary view, terrible for performance, good for testing
     body = body || {};
-    Object.keys(fun).forEach(function (key) {
+    for (const key of Object.keys(fun)) {
       if (Array.isArray(fun[key])) {
         body[key] = fun[key];
       } else {
         body[key] = fun[key].toString();
       }
-    });
+    }
 
     const response = await db.fetch('_temp_view' + params, {
       headers: new Headers({'Content-Type': 'application/json'}),
@@ -412,8 +412,7 @@ function createAbstractMapReduce(localDocName, mapper, reducer, ddocValidator) {
       const kvDocs = [];
       const oldKeys = new Set();
 
-      for (let i = 0, len = kvDocsRes.rows.length; i < len; i++) {
-        const row = kvDocsRes.rows[i];
+      for (const row of kvDocsRes.rows) {
         const doc = row.doc;
         if (!doc) { // deleted
           continue;
@@ -429,7 +428,7 @@ function createAbstractMapReduce(localDocName, mapper, reducer, ddocValidator) {
         }
       }
       const newKeys = mapToKeysArray(indexableKeysToKeyValues);
-      newKeys.forEach(function (key) {
+      for (const key of newKeys) {
         if (!oldKeys.has(key)) {
           // new doc
           const kvDoc = {
@@ -441,7 +440,7 @@ function createAbstractMapReduce(localDocName, mapper, reducer, ddocValidator) {
           }
           kvDocs.push(kvDoc);
         }
-      });
+      }
       metaDoc.keys = uniq(newKeys.concat(metaDoc.keys));
       kvDocs.push(metaDoc);
 
@@ -650,8 +649,7 @@ function createAbstractMapReduce(localDocName, mapper, reducer, ddocValidator) {
 
     function createDocIdsToChangesAndEmits(results) {
       const docIdsToChangesAndEmits = new Map();
-      for (let i = 0, len = results.length; i < len; i++) {
-        const change = results[i];
+      for (const change of results) {
         if (change.doc._id[0] !== '_') {
           mapResults = [];
           doc = change.doc;
@@ -704,48 +702,48 @@ function createAbstractMapReduce(localDocName, mapper, reducer, ddocValidator) {
     }
 
     const shouldGroup = options.group || options.group_level;
-
     const reduceFun = reducer(view.reduceFun);
-
     const groups = [];
-    const lvl = isNaN(options.group_level) ? Number.POSITIVE_INFINITY :
-      options.group_level;
-    results.forEach(function (e) {
+    const lvl = isNaN(options.group_level)
+      ? Number.POSITIVE_INFINITY
+      : options.group_level;
+
+    for (const result of results) {
       const last = groups[groups.length - 1];
-      let groupKey = shouldGroup ? e.key : null;
+      let groupKey = shouldGroup ? result.key : null;
 
       // only set group_level for array keys
       if (shouldGroup && Array.isArray(groupKey)) {
         groupKey = groupKey.slice(0, lvl);
       }
 
       if (last && collate(last.groupKey, groupKey) === 0) {
-        last.keys.push([e.key, e.id]);
-        last.values.push(e.value);
-        return;
+        last.keys.push([result.key, result.id]);
+        last.values.push(result.value);
+        continue;
       }
       groups.push({
-        keys: [[e.key, e.id]],
-        values: [e.value],
+        keys: [[result.key, result.id]],
+        values: [result.value],
         groupKey
       });
-    });
+    }
+
     results = [];
-    for (let i = 0, len = groups.length; i < len; i++) {
-      const e = groups[i];
-      const reduceTry = tryReduce(view.sourceDB, reduceFun, e.keys, e.values, false);
+    for (const group of groups) {
+      const reduceTry = tryReduce(view.sourceDB, reduceFun, group.keys, group.values, false);
       if (reduceTry.error && reduceTry.error instanceof BuiltInError) {
         // CouchDB returns an error if a built-in errors out
         throw reduceTry.error;
       }
       results.push({
         // CouchDB just sets the value to null if a non-built-in errors out
         value: reduceTry.error ? null : reduceTry.output,
-        key: e.groupKey
+        key: group.groupKey
       });
     }
     // no total_rows/offset when reducing
-    return {rows: sliceResults(results, options.limit, options.skip)};
+    return { rows: sliceResults(results, options.limit, options.skip) };
   }
 
   function queryView(view, opts) {
@@ -827,20 +825,18 @@ function createAbstractMapReduce(localDocName, mapper, reducer, ddocValidator) {
           binary: opts.binary
         });
         const docIdsToDocs = new Map();
-        allDocsRes.rows.forEach(function (row) {
+        for (const row of allDocsRes.rows) {
           docIdsToDocs.set(row.id, row.doc);
-        });
-        rows.forEach(function (row) {
+        }
+        for (const row of rows) {
           const docId = rowToDocId(row);
           const doc = docIdsToDocs.get(docId);
           if (doc) {
             row.doc = doc;
           }
-        });
-        return finalResults;
-      } else {
-        return finalResults;
+        }
       }
+      return finalResults;
     }
 
     if (typeof opts.keys !== 'undefined') {
@@ -931,7 +927,7 @@ function createAbstractMapReduce(localDocName, mapper, reducer, ddocValidator) {
       const metaDoc = await db.get('_local/' + localDocName);
       const docsToViews = new Map();
 
-      Object.keys(metaDoc.views).forEach(function (fullViewName) {
+      for (const fullViewName of Object.keys(metaDoc.views)) {
         const parts = parseViewName(fullViewName);
         const designDocName = '_design/' + parts[0];
         const viewName = parts[1];
@@ -941,17 +937,17 @@ function createAbstractMapReduce(localDocName, mapper, reducer, ddocValidator) {
           docsToViews.set(designDocName, views);
         }
         views.add(viewName);
-      });
+      }
       const opts = {
         keys : mapToKeysArray(docsToViews),
         include_docs : true
       };
 
       const res = await db.allDocs(opts);
       const viewsToStatus = {};
-      res.rows.forEach(function (row) {
+      for (const row of res.rows) {
         const ddocName = row.key.substring(8); // cuts off '_design/'
-        docsToViews.get(row.key).forEach(function (viewName) {
+        for (const viewName of docsToViews.get(row.key)) {
           let fullViewName = ddocName + '/' + viewName;
           /* istanbul ignore if */
           if (!metaDoc.views[fullViewName]) {
@@ -963,12 +959,11 @@ function createAbstractMapReduce(localDocName, mapper, reducer, ddocValidator) {
           // design doc deleted, or view function nonexistent
           const statusIsGood = row.doc && row.doc.views &&
             row.doc.views[viewName];
-          viewDBNames.forEach(function (viewDBName) {
-            viewsToStatus[viewDBName] =
-              viewsToStatus[viewDBName] || statusIsGood;
-          });
-        });
-      });
+          for (const viewDBName of viewDBNames) {
+            viewsToStatus[viewDBName] = viewsToStatus[viewDBName] || statusIsGood;
+          }
+        }
+      }
 
       const dbsToDelete = Object.keys(viewsToStatus)
         .filter(function (viewDBName) { return !viewsToStatus[viewDBName]; });