duckdb · jraymakers · Jan 19, 2025 · Jan 19, 2025
diff --git a/api/src/DuckDBDataChunk.ts b/api/src/DuckDBDataChunk.ts
@@ -1,5 +1,6 @@
 import duckdb from '@duckdb/node-bindings';
 import { DuckDBType } from './DuckDBType';
+import { DuckDBValueConverter } from './DuckDBValueConverter';
 import { DuckDBVector } from './DuckDBVector';
 import { DuckDBValue } from './values';
 
@@ -49,19 +50,32 @@ export class DuckDBDataChunk {
     visitValue: (
       value: DuckDBValue,
       rowIndex: number,
-      columnIndex: number
+      columnIndex: number,
+      type: DuckDBType
     ) => void
   ) {
     const vector = this.getColumnVector(columnIndex);
+    const type = vector.type;
     for (let rowIndex = 0; rowIndex < vector.itemCount; rowIndex++) {
-      visitValue(vector.getItem(rowIndex), rowIndex, columnIndex);
+      visitValue(vector.getItem(rowIndex), rowIndex, columnIndex, type);
     }
   }
   public getColumnValues(columnIndex: number): DuckDBValue[] {
     const values: DuckDBValue[] = [];
     this.visitColumnValues(columnIndex, (value) => values.push(value));
     return values;
   }
+  public convertColumnValues<T>(
+    columnIndex: number,
+    converter: DuckDBValueConverter<T>
+  ): T[] {
+    const convertedValues: T[] = [];
+    const type = this.getColumnVector(columnIndex).type;
+    this.visitColumnValues(columnIndex, (value) =>
+      convertedValues.push(converter.convertValue(value, type))
+    );
+    return convertedValues;
+  }
   public setColumnValues(columnIndex: number, values: readonly DuckDBValue[]) {
     const vector = this.getColumnVector(columnIndex);
     if (vector.itemCount !== values.length) {
@@ -73,18 +87,34 @@ export class DuckDBDataChunk {
     vector.flush();
   }
   public visitColumns(
-    visitColumn: (column: DuckDBValue[], columnIndex: number) => void
+    visitColumn: (
+      column: DuckDBValue[],
+      columnIndex: number,
+      type: DuckDBType
+    ) => void
   ) {
     const columnCount = this.columnCount;
     for (let columnIndex = 0; columnIndex < columnCount; columnIndex++) {
-      visitColumn(this.getColumnValues(columnIndex), columnIndex);
+      visitColumn(
+        this.getColumnValues(columnIndex),
+        columnIndex,
+        this.getColumnVector(columnIndex).type
+      );
     }
   }
   public getColumns(): DuckDBValue[][] {
     const columns: DuckDBValue[][] = [];
     this.visitColumns((column) => columns.push(column));
     return columns;
   }
+  public convertColumns<T>(converter: DuckDBValueConverter<T>): T[][] {
+    const convertedColumns: T[][] = [];
+    const columnCount = this.columnCount;
+    for (let columnIndex = 0; columnIndex < columnCount; columnIndex++) {
+      convertedColumns.push(this.convertColumnValues(columnIndex, converter));
+    }
+    return convertedColumns;
+  }
   public setColumns(columns: readonly (readonly DuckDBValue[])[]) {
     if (columns.length > 0) {
       this.rowCount = columns[0].length;
@@ -97,7 +127,8 @@ export class DuckDBDataChunk {
     visitValue: (
       value: DuckDBValue,
       rowIndex: number,
-      columnIndex: number
+      columnIndex: number,
+      type: DuckDBType
     ) => void
   ) {
     const columnCount = this.columnCount;
@@ -110,23 +141,33 @@ export class DuckDBDataChunk {
     visitValue: (
       value: DuckDBValue,
       rowIndex: number,
-      columnIndex: number
+      columnIndex: number,
+      type: DuckDBType
     ) => void
   ) {
     const columnCount = this.columnCount;
     for (let columnIndex = 0; columnIndex < columnCount; columnIndex++) {
-      visitValue(
-        this.getColumnVector(columnIndex).getItem(rowIndex),
-        rowIndex,
-        columnIndex
-      );
+      const vector = this.getColumnVector(columnIndex);
+      visitValue(vector.getItem(rowIndex), rowIndex, columnIndex, vector.type);
     }
   }
   public getRowValues(rowIndex: number): DuckDBValue[] {
     const values: DuckDBValue[] = [];
     this.visitRowValues(rowIndex, (value) => values.push(value));
     return values;
   }
+  public convertRowValues<T>(
+    rowIndex: number,
+    converter: DuckDBValueConverter<T>
+  ): T[] {
+    const convertedValues: T[] = [];
+    this.visitRowValues(rowIndex, (value, _, columnIndex) =>
+      convertedValues.push(
+        converter.convertValue(value, this.getColumnVector(columnIndex).type)
+      )
+    );
+    return convertedValues;
+  }
   public visitRows(visitRow: (row: DuckDBValue[], rowIndex: number) => void) {
     const rowCount = this.rowCount;
     for (let rowIndex = 0; rowIndex < rowCount; rowIndex++) {
@@ -138,6 +179,14 @@ export class DuckDBDataChunk {
     this.visitRows((row) => rows.push(row));
     return rows;
   }
+  public convertRows<T>(converter: DuckDBValueConverter<T>): T[][] {
+    const convertedRows: T[][] = [];
+    const rowCount = this.rowCount;
+    for (let rowIndex = 0; rowIndex < rowCount; rowIndex++) {
+      convertedRows.push(this.convertRowValues(rowIndex, converter));
+    }
+    return convertedRows;
+  }
   public setRows(rows: readonly (readonly DuckDBValue[])[]) {
     this.rowCount = rows.length;
     const columnCount = this.columnCount;
@@ -153,17 +202,20 @@ export class DuckDBDataChunk {
     visitValue: (
       value: DuckDBValue,
       rowIndex: number,
-      columnIndex: number
+      columnIndex: number,
+      type: DuckDBType
     ) => void
   ) {
     const rowCount = this.rowCount;
     const columnCount = this.columnCount;
     for (let rowIndex = 0; rowIndex < rowCount; rowIndex++) {
       for (let columnIndex = 0; columnIndex < columnCount; columnIndex++) {
+        const vector = this.getColumnVector(columnIndex);
         visitValue(
-          this.getColumnVector(columnIndex).getItem(rowIndex),
+          vector.getItem(rowIndex),
           rowIndex,
-          columnIndex
+          columnIndex,
+          vector.type
         );
       }
     }

diff --git a/api/src/DuckDBResult.ts b/api/src/DuckDBResult.ts
@@ -3,6 +3,11 @@ import { DuckDBDataChunk } from './DuckDBDataChunk';
 import { DuckDBLogicalType } from './DuckDBLogicalType';
 import { DuckDBType } from './DuckDBType';
 import { DuckDBTypeId } from './DuckDBTypeId';
+import { DuckDBValueToJsonConverter, Json } from './DuckDBValueToJsonConverter';
+import { convertColumnsFromChunks } from './convertColumnsFromChunks';
+import { convertColumnsObjectFromChunks } from './convertColumnsObjectFromChunks';
+import { convertRowObjectsFromChunks } from './convertRowObjectsFromChunks';
+import { convertRowsFromChunks } from './convertRowsFromChunks';
 import { ResultReturnType, StatementType } from './enums';
 import { getColumnsFromChunks } from './getColumnsFromChunks';
 import { getColumnsObjectFromChunks } from './getColumnsObjectFromChunks';
@@ -99,16 +104,40 @@ export class DuckDBResult {
     const chunks = await this.fetchAllChunks();
     return getColumnsFromChunks(chunks);
   }
+  public async getColumnsJson(): Promise<Json[][]> {
+    const chunks = await this.fetchAllChunks();
+    return convertColumnsFromChunks(chunks, DuckDBValueToJsonConverter.default);
+  }
   public async getColumnsObject(): Promise<Record<string, DuckDBValue[]>> {
     const chunks = await this.fetchAllChunks();
     return getColumnsObjectFromChunks(chunks, this.deduplicatedColumnNames());
   }
+  public async getColumnsObjectJson(): Promise<Record<string, Json[]>> {
+    const chunks = await this.fetchAllChunks();
+    return convertColumnsObjectFromChunks(
+      chunks,
+      this.deduplicatedColumnNames(),
+      DuckDBValueToJsonConverter.default
+    );
+  }
   public async getRows(): Promise<DuckDBValue[][]> {
     const chunks = await this.fetchAllChunks();
     return getRowsFromChunks(chunks);
   }
+  public async getRowsJson(): Promise<Json[][]> {
+    const chunks = await this.fetchAllChunks();
+    return convertRowsFromChunks(chunks, DuckDBValueToJsonConverter.default);
+  }
   public async getRowObjects(): Promise<Record<string, DuckDBValue>[]> {
     const chunks = await this.fetchAllChunks();
     return getRowObjectsFromChunks(chunks, this.deduplicatedColumnNames());
   }
+  public async getRowObjectsJson(): Promise<Record<string, Json>[]> {
+    const chunks = await this.fetchAllChunks();
+    return convertRowObjectsFromChunks(
+      chunks,
+      this.deduplicatedColumnNames(),
+      DuckDBValueToJsonConverter.default
+    );
+  }
 }
diff --git a/api/src/DuckDBResultReader.ts b/api/src/DuckDBResultReader.ts
@@ -1,8 +1,13 @@
+import { convertColumnsFromChunks } from './convertColumnsFromChunks';
+import { convertColumnsObjectFromChunks } from './convertColumnsObjectFromChunks';
+import { convertRowObjectsFromChunks } from './convertRowObjectsFromChunks';
+import { convertRowsFromChunks } from './convertRowsFromChunks';
 import { DuckDBDataChunk } from './DuckDBDataChunk';
 import { DuckDBLogicalType } from './DuckDBLogicalType';
 import { DuckDBResult } from './DuckDBResult';
 import { DuckDBType } from './DuckDBType';
 import { DuckDBTypeId } from './DuckDBTypeId';
+import { DuckDBValueToJsonConverter, Json } from './DuckDBValueToJsonConverter';
 import { ResultReturnType, StatementType } from './enums';
 import { getColumnsFromChunks } from './getColumnsFromChunks';
 import { getColumnsObjectFromChunks } from './getColumnsObjectFromChunks';
@@ -163,15 +168,48 @@ export class DuckDBResultReader {
     return getColumnsFromChunks(this.chunks);
   }
 
+  public getColumnsJson(): Json[][] {
+    return convertColumnsFromChunks(
+      this.chunks,
+      DuckDBValueToJsonConverter.default
+    );
+  }
+
   public getColumnsObject(): Record<string, DuckDBValue[]> {
-    return getColumnsObjectFromChunks(this.chunks, this.deduplicatedColumnNames());
+    return getColumnsObjectFromChunks(
+      this.chunks,
+      this.deduplicatedColumnNames()
+    );
+  }
+
+  public getColumnsObjectJson(): Record<string, Json[]> {
+    return convertColumnsObjectFromChunks(
+      this.chunks,
+      this.deduplicatedColumnNames(),
+      DuckDBValueToJsonConverter.default
+    );
   }
 
   public getRows(): DuckDBValue[][] {
     return getRowsFromChunks(this.chunks);
   }
 
-  public getRowObjecs(): Record<string, DuckDBValue>[] {
+  public getRowsJson(): Json[][] {
+    return convertRowsFromChunks(
+      this.chunks,
+      DuckDBValueToJsonConverter.default
+    );
+  }
+
+  public getRowObjects(): Record<string, DuckDBValue>[] {
     return getRowObjectsFromChunks(this.chunks, this.deduplicatedColumnNames());
   }
+
+  public getRowObjectsJson(): Record<string, Json>[] {
+    return convertRowObjectsFromChunks(
+      this.chunks,
+      this.deduplicatedColumnNames(),
+      DuckDBValueToJsonConverter.default
+    );
+  }
 }
diff --git a/api/src/DuckDBType.ts b/api/src/DuckDBType.ts
@@ -576,6 +576,7 @@ export function LIST(valueType: DuckDBType, alias?: string): DuckDBListType {
 export class DuckDBStructType extends BaseDuckDBType<DuckDBTypeId.STRUCT> {
   public readonly entryNames: readonly string[];
   public readonly entryTypes: readonly DuckDBType[];
+  public readonly entryIndexes: Readonly<Record<string, number>>;
   public constructor(
     entryNames: readonly string[],
     entryTypes: readonly DuckDBType[],
@@ -588,10 +589,21 @@ export class DuckDBStructType extends BaseDuckDBType<DuckDBTypeId.STRUCT> {
     }
     this.entryNames = entryNames;
     this.entryTypes = entryTypes;
+    const entryIndexes: Record<string, number> = {};
+    for (let i = 0; i < entryNames.length; i++) {
+      entryIndexes[entryNames[i]] = i;
+    }
+    this.entryIndexes = entryIndexes;
   }
   public get entryCount() {
     return this.entryNames.length;
   }
+  public indexForEntry(entryName: string): number {
+    return this.entryIndexes[entryName];
+  }
+  public typeForEntry(entryName: string): DuckDBType {
+    return this.entryTypes[this.entryIndexes[entryName]];
+  }
   public toString(): string {
     const parts: string[] = [];
     for (let i = 0; i < this.entryNames.length; i++) {
@@ -727,6 +739,9 @@ export class DuckDBUnionType extends BaseDuckDBType<DuckDBTypeId.UNION> {
   public memberIndexForTag(tag: string): number {
     return this.tagMemberIndexes[tag];
   }
+  public memberTypeForTag(tag: string): DuckDBType {
+    return this.memberTypes[this.tagMemberIndexes[tag]];
+  }
   public get memberCount() {
     return this.memberTags.length;
   }

diff --git a/api/src/DuckDBValueConverter.ts b/api/src/DuckDBValueConverter.ts
@@ -0,0 +1,6 @@
+import { DuckDBType } from './DuckDBType';
+import { DuckDBValue } from './values';
+
+export interface DuckDBValueConverter<T> {
+  convertValue(value: DuckDBValue, type: DuckDBType): T;
+}