fillCells

Extend a selection by filling cells with auto-detected patterns (numbers, dates, formulas). Similar to Excel’s fill handle - detects sequences and continues them. Fill direction is inferred from selection and extend_to: the dimension that changes determines the fill axis.

IMPORTANT: After filling, you MUST call editCellStyles to apply formatting to the filled cells.

Examples:

• Fill down: { “sheet”: “Sheet1”, “selection”: “A1:A3”, “extend_to”: “A1:A10”, “note”: “Extend series” }
• Fill right: { “sheet”: “Sheet1”, “selection”: “A1:C1”, “extend_to”: “A1:F1”, “note”: “Extend headers” }
• Fill up: { “sheet”: “Sheet1”, “selection”: “A8:B10”, “extend_to”: “A1:B10”, “note”: “Extend upward” }

Parameter	Type		Description
sheet	string	required	Sheet name to operate on
selection	string	required	Source range containing the pattern (e.g., “A1:A3”)
extend_to	string	required	Target range to fill to (e.g., “A1:A10”)
note	string	required	Description of this operation for version history