How to schedule a trigger on a script - google-apps-script

Question

The situation:
I have sheet containing JSON data that collects personal trading information from a stock exchange. When this API feed retrieves a new line of information (after a new trade has been placed) I need that to act as a trigger to run two Google Scripts to perform their function. These scripts can only be triggered when a new trade has been made, not on a regular time-based trigger.
What have I tried:
Initially, I started off trying onChange/onEdit however, both options will not work because onChange/onEdit search for user-made edits to the cell, which changes to an API feed are not. Because there is no material change to the formula and therefore onChange/onEdit do not react to trigger the script. I have also tried to find a solution for a trigger to activate a script on changes made within a formula (therefore to allow for new data to arriving through an API to trigger the script), but that doesn't appear to be possible.
What am I trying to achieve right now:
I am considering the possibility of establishing a time scheduled trigger via Scripts. Within the API feed, I get confirmation of the date and time a trade has been made. I plan for the script to search the lastRow of certain columns to identify a date and time to trigger this time scheduled script, which in turn will trigger the two other scripts mentioned above.
My coding:
function createTimeDrivenTriggers() {
// Trigger on 2019-12-11 at 21:00.
ScriptApp.newTrigger('priceCalc')
.timeBased()
.atDate(2019, 12, 11)
.atHour(21)
.create();
}
Explanation on coding:
Eventually, the information held within the .atDate() and .atHour() strings will contain information drawn from the lastRow of different columns on Google Sheets to identify the correct integer to feed in to this script. But for now, I am just trying to get this script to work based on fixed values.
In this example above, on 11th December 2019 at 21:00, the createTimeDrivenTriggers script should be triggered, which in turn runs the priceCalc script.
Questions:
1) I cannot get this script to work correctly at the date/time given. What am I doing wrong?
2) I also need to incorporate an .atMinute() and .atSecond() strings here, but that doesn't seem to be available. Can anyone advise how to incorporate this?
3) Finally, if anyone can think of a better way to find a solution for this other than a time scheduled trigger, I am happy to consider other options.
I am very much a novice of scripts, so helpful advise to sort my issue would be greatly appreciated. I have spent days trying to find a solution without any luck.

Answer 1

You can not use atDate(year, month, day) and atHour(hour) together
Indeed, the documentation specifies:
Frequency is required if you are using atHour() or nearMinute()
Instead, you can use at(date) with a date-time string, with the corresponding Javascript syntax.
Sample:
function createTimeDrivenTriggers() {
// Trigger on 2019-12-11 at 21:00.
var time=new Date('2019-12-12T21:00:00');
ScriptApp.newTrigger('priceCalc')
.timeBased()
.at(time)
.create();
}

Answer 2

When you run your code, it generates an error message:
Already chosen a specific date time with at() or atDate()....
What it means is that you cannot use both atDate() and atHour() in the same script.
The solution to creating a "time-of-day-and-hour" trigger is to use at().
The benefit of this is that you can specify a time interval down to seconds and milliseconds.
However, do not be misled. Google undertakes that the script will execute within +/-15 minutes from the specified time. So incorporating "second" parameters might make you feel good, but isn't guaranteed to make any real difference.
Props: #SpencerEaston (https://stackoverflow.com/a/30458103/1330560) for the definition of the date which may well be in the documentation, but I couldn't see it.
For example:
function createTimeDrivenTriggers() {
// Trigger on 2019-12-12 at 21:00.
//var d = new Date(year, month, day, hours, minutes, seconds, milliseconds);
var d = new Date(2019, 12, 12, 21, 00, 00, 00);
ScriptApp.newTrigger('triggertest')
.timeBased()
.at(d)
.create();
}