n8n/packages/nodes-base/nodes/MySql/GenericFunctions.ts

import {
	IDataObject,
	INodeExecutionData,
} from 'n8n-workflow';

/**
 * Returns of copy of the items which only contains the json data and
 * of that only the define properties
 *
 * @param {INodeExecutionData[]} items The items to copy
 * @param {string[]} properties The properties it should include
 * @returns
 */
export function copyInputItems(items: INodeExecutionData[], properties: string[]): IDataObject[] {
	// Prepare the data to insert and copy it to be returned
	let newItem: IDataObject;
	return items.map((item) => {
		newItem = {};
		for (const property of properties) {
			if (item.json[property] === undefined) {
				newItem[property] = null;
			} else {
				newItem[property] = JSON.parse(JSON.stringify(item.json[property]));
			}
		}
		return newItem;
	});
}