recordTimerAuto.js

/**
 * Title: Record Timer (Automation)
 * Version: 1.0
 * License: MIT
 * Author: Justin S Barrett
 * Sites:
 * http://www.justinsbarrett.com - Main website
 * https://www.youtube.com/channel/UCElPqW_1xVXToQPB3Y_WD3Q - All About That Base
 * 
 * Description: An alternative to Airtable's built-in timer block. With this script,
 * you can start and stop virtual timers directly on individual records. Any record's
 * timer may be started and stopped multiple times, allowing for easy tracking of
 * staggered timing sessions. This version is designed to be triggered by Airtable's
 * automation system.
 *  
 * Requirements: Before using this script, you will need to add the following fields:
 * - A single select field to start/stop the timer. This should only contain one
 *   option. The text of that option is irrelevant, but I like "Running" which
 *   serves as a visual reminder of that record's timer state
 * - A single line text field to store the timer data (may be hidden)
 * - A duration field to store the total tracked time
 * 
 * Automation Setup: The automation must use the "When a record is updated" trigger,
 * which will look for changes to the single select field mentioned above.
 * 
 * Input Variables: The following input variables must be added to the script action:
 *  timerData       Data from the single line text field that stores timer data
 *  triggerValue    The "Name" property of the single select field driving the timer
 *  recordID        The record ID of the triggering record
 * 
 * Version History:
 * 09/11/2020   1.0     Initial release
 * 
 */

// Get the record
let config = input.config();
let timerData = config.timerData;
let values = timerData === null ? [] : JSON.parse(timerData);
let duration;

// Get the current time and store its value in the array
let currentTime = new Date();
values.push(currentTime.getTime());

// Check the trigger field value to see if we're starting or stopping
if (config.triggerValue) {
    // Not-empty = starting. Clear the duration field
    duration = null;
} else {
    // Empty = stopping. Find the difference between the value pairs
    duration = 0;
    let index = 0;
    while (values.length % 2 == 0 && index<values.length) {
        duration += values[index + 1] - values[index];
        index += 2;
    }
    // Divide by 1000 to get seconds
    duration /= 1000;
}

// Save output values
output.set("duration", duration);
output.set("timerData", JSON.stringify(values));