Refactored #25 into helper function and fixed flow issues

Author: tmitchel2

src/Provisioner.js

@@ -20,20 +20,7 @@ export default class Provisioner extends ProvisionerConfigurableBase {
   async getTableNamesAsync(): Promise<string[]> {
 
     // Option 1 - All tables (Default)
-    //   The output from ListTables is paginated, with each page
-    //   returning a maximum of 100 table names.
-    let listTablesResponse = await this.db.listTablesAsync();
-    var tableNames = listTablesResponse.TableNames;
-    var lastTable = listTablesResponse.LastEvaluatedTableName;
-
-    while (lastTable) {
-      var params = { ExclusiveStartTableName: lastTable };
-      let listTablesResponse = await this.db.listTablesAsync(params);
-      tableNames = tableNames.concat(listTablesResponse.TableNames);
-      lastTable = listTablesResponse.LastEvaluatedTableName;
-    }
-
-    return tableNames;
+    return await this.db.listAllTableNamesAsync();
 
     // Option 2 - Hardcoded list of tables
     // return ['Table1', 'Table2', 'Table3'];

src/aws/DynamoDB.js

@@ -46,6 +46,17 @@ export default class DynamoDB {
     }
   }
 
+  async listAllTableNamesAsync(): Promise<string[]> {
+    let tableNames = [];
+    let lastTable;
+    do {
+      let listTablesResponse = await this.listTablesAsync({ ExclusiveStartTableName: lastTable });
+      tableNames = tableNames.concat(listTablesResponse.TableNames);
+      lastTable = listTablesResponse.LastEvaluatedTableName;
+    } while (lastTable);
+    return tableNames;
+  }
+
   async describeTableAsync(params: DescribeTableRequest): Promise<DescribeTableResponse> {
     let sw = stats.timer('DynamoDB.describeTableAsync').start();
     try {