Scheduled SuiteScript to load a CSV from File Cabinet and append saved search results to CSV and save

I am attempting to create a historical csv backup (appended rather than overwritten) to our file cabinet using a saved searches results (on a once a week schedule).

I know its possible to write a saved searches results to a CSV (using task), but I'm not sure how I can append instead (maybe using file.appendline?). Here is what I've come up with which results in the appended data being "task.SearchTask" instead of the saved search results:

/**
 * @NApiVersion 2.1
 * @NScriptType ScheduledScript
 */
define(['N/file', 'N/task'],
    /**
 * @param{file} file
 * @param{task} task
 */
    (file, task) => {

        /**
         * Defines the Scheduled script trigger point.
         * @param {Object} scriptContext
         * @param {string} scriptContext.type - Script execution context. Use values from the scriptContext.InvocationType enum.
         * @since 2015.2
         */

        //[file ID, Saved Search ID]
        const keys = [
            [72567, 1701]
        ]

        const execute = (scriptContext) => {
            for(var i = 0; i < keys.length; i++) {
                var searchTask = task.create({
                    taskType: task.TaskType.SEARCH,
                    savedsearchId: keys[i][1]
                });

                var csvFile = file.load({
                    id: keys[i][0]
                });

                //This probably doesn't work...
                csvFile.appendLine({
                    value: searchTask
                });

                csvFile.save();
            }
        }

        return {execute}

    });

Any assistance would be appreciated!

The issue you're encountering is because task.create() doesn't directly return the results of the saved search; instead, it returns a SearchTask object representing the background task. You need to execute the search, fetch the results, and append them to the CSV file. Here's a corrected approach:

1. Use task.create() to initiate the search task.

2. Retrieve the saved search results using search.run() or search.runPaged().

3. Append the results to the CSV file.

    /**
     * @NApiVersion 2.1
     * @NScriptType ScheduledScript
     */
    define(['N/file', 'N/search', 'N/task', 'N/log'],
        (file, search, task, log) => {
    
            const keys = [
                [72567, 1701] // File ID, Saved Search ID
            ];
    
            const execute = (scriptContext) => {
                keys.forEach(([fileId, savedSearchId]) => {
    
                    // Load the CSV file from the file cabinet
                    var csvFile = file.load({
                        id: fileId
                    });
    
                    // Create a search object using the saved search ID
                    var searchObj = search.load({
                        id: savedSearchId
                    });
    
                    // Run the search and get the results in pages to avoid memory issues
                    var pagedResults = searchObj.runPaged({
                        pageSize: 1000 // Adjust as needed
                    });
    
                    pagedResults.pageRanges.forEach(function (pageRange) {
                        var page = pagedResults.fetch({
                            index: pageRange.index
                        });
    
                        page.data.forEach(function (result) {
                            var csvLine = result.columns.map(col => result.getValue(col)).join(',');
                            csvFile.appendLine({
                                value: csvLine
                            });
                        });
                    });
    
                    // Save the appended CSV file back to the file cabinet
                    csvFile.save();
                });
            };
    
            return { execute };
        });