(#3) Added TRUNCATE RTINDEX

Author: SiroDiaz

src/QueryBuilder.ts

@@ -5,6 +5,7 @@ import TransactionStatement from './Statements/TransactionStatement';
 import UpdateStatement from './Statements/UpdateStatement';
 import DeleteStatement from './Statements/DeleteStatement';
 import AttachIndexStatement from './Statements/AttachIndexStatement';
+import TruncateStatement from './Statements/TruncateStatement';
 
 export default class QueryBuilder {
   // protected type: QueryType;
@@ -55,6 +56,10 @@ export default class QueryBuilder {
     return new AttachIndexStatement(this.connection, diskIndex);
   }
 
+  public truncate(rtIndex: string): TruncateStatement {
+    return new TruncateStatement(this.connection, rtIndex);
+  }
+
   get transaction(): TransactionStatement {
     return new TransactionStatement(this.connection);
   }

src/Statements/AttachIndexStatement.ts

@@ -46,4 +46,4 @@ export default class AttachIndexStatement {
   execute(): Promise<any> {
     return this.connection.execute(this.generate(), []);
   }
-}
+}

src/Statements/TruncateStatement.ts

@@ -0,0 +1,39 @@
+import ClientInterface from '../ClientInterface';
+
+/**
+ * TRUNCATE RTINDEX rtindex [WITH RECONFIGURE]
+ */
+export default class TruncateStatement {
+  protected reconfigure: boolean = false;
+
+  public constructor(protected connection: ClientInterface, protected rtIndex: string) {}
+
+  /**
+   * When RECONFIGURE option is used new tokenization, morphology,
+   * and other text processing settings from config take effect
+   * right after index got cleared. This allows to make operations atomic.
+   */
+  public withReconfigure(): TruncateStatement {
+    this.reconfigure = true;
+    return this;
+  }
+
+  /**
+   * Generates the string statement.
+   */
+  generate(): string {
+    let expression: string = `TRUNCATE RTINDEX ${this.rtIndex}`;
+    if (this.reconfigure) {
+      expression += ` WITH RECONFIGURE`;
+    }
+    
+    return expression;
+  }
+
+  /**
+   * Run the query and returns a promise that can be accepted or rejected.
+   */
+  execute(): Promise<any> {
+    return this.connection.execute(this.generate(), []);
+  }
+}