Function computeFillValues

Computes the values of a fill (fill handle, Ctrl/⌘+D): count values that continue sourceValues – forward (down/right) or backward (up/left: the value directly in front of the source first).

source	"auto"	"alternate"
one number 5	5, 5, 5	6, 7, 8
numbers 1, 2	3, 4, 5 (linear; uneven steps: best-fit line)	1, 2, 1
date 2026-10-14 (Date or ISO text)	+1 day each; several dates a month apart: +1 month (month ends stay month ends)	copied
text with a trailing number Item 9	Item 10, Item 11 (leading zeros stay)	copied
anything else	repeated: A, B → A, B, A, B	repeated

The type stays: a date text stays a text in the same format, a Date stays a Date, a number written as text stays a text. Decimal noise is rounded (0.1, 0.2 → 0.3, not 0.30000000000000004).

Example

computeFillValues([1, 2], 3);                       // [3, 4, 5]
computeFillValues([5], 3);                          // [5, 5, 5]
computeFillValues([5], 3, false, "alternate");      // [6, 7, 8]
computeFillValues(["2026-10-14"], 2);               // ["2026-10-15", "2026-10-16"]
computeFillValues(["Item 9"], 2);                   // ["Item 10", "Item 11"]
computeFillValues([1, 2], 2, true);                 // [0, -1]  (filled upwards)
Copy

Since

1.1.96