toMillis returns incorrect timestamp with more then 3 digits in fractional seconds

[deity-bram]

Using this a picture and date with a more precise format then 3 digits returns an invalid timestamp.

While not using a picture returns the correct timestamp.

$toMillis("2026-04-08T19:05:04.94756", "[Y0001]-[M01]-[D01]T[H01]:[m01]:[s01].[f1]")

Will return 1775675198756 (2026-04-08T19:06:38.756Z)

While it should 1775667904947 (2026-04-08T17:05:04.947Z)

This will happen if you use fractional precision. [f1], or specifying the decimals f[00001].

Code snippet

const JSONata = require("jsonata");

const inputData = "2026-04-08T19:05:04.94756";   // Change timestamp
let mapping = `$toMillis($, "[Y0001]-[M01]-[D01]T[H01]:[m01]:[s01].[f1]")`; // change or remove picture

(async () => {
  const expression = JSONata(mapping);
  const transformedData = await expression.evaluate(inputData);
  const dDate = new Date(transformedData);

  console.log(`input              :${inputData}`);
  console.log(`timestamp     :${transformedData}`);
  console.log(`date               :${dDate.toISOString()}`);
})();