Appends rows to a Google Sheet using the specified OAuth2 token and spreadsheet id.

appendRowsToSheet.js

/**
 * Appends the row matrix to the specified range in the identified sheet.
 * 
 * @param {string} token an OAuth2 token scoped for write to the Google sheets APIs
 *   (scope must include "https://www.googleapis.com/auth/spreadsheets") and with access
 *   to the underlying Google Sheet. The Sheet should be shared with the service user's
 *   email address.
 * @param {string} spreadsheetId the spreadsheet's identifier, which you can glean
 *   from the Google Sheets URL, extracted from the pattern:
 *   https://docs.google.com/spreadsheets/d/([A-Za-z0-9_-]+)/edit#gid=0
 * @param {string} range the range to append to, for the home row this is "A1:A1"
 * @param {string[][]} rows the rows to append, must be an array of an array of strings
 * @returns the Google API result object
 */
async function appendRowsToSheet(token, spreadsheetId, range, rows) {
  try {
    return await fetch(
      `https://sheets.googleapis.com/v4/spreadsheets/${spreadsheetId}/values/${range}:append?valueInputOption=USER_ENTERED`,
      {
        "method": "POST",
        headers: {
          "Content-Type": "application/json",
          "Authorization": "Bearer " + token
        },
        body: JSON.stringify({
          "range": range,
          "majorDimension": "rows",
          "values": rows
        })
      })
  } catch (err) {
    console.log(err)
  }
}