Interface ICondition<P>

Remarks

The operator is responsible for evaluating the condition param against the transformed value from the selector. Return null if there is no operator and the condition is purely based on the selector transformation (e.g. "Is Blank" could be a selector that checks for blank values without needing an operator).

Remarks

This is operator-specific and not all operators require a param.

Remarks

The selector is responsible for transforming the cell value before it is passed to the operator predicate. If null is returned then the raw cell value is used (identity selector). This allows operators to focus on their core logic and delegate any necessary value transformation to the selector. For example, a "Text Contains" operator might use a selector that converts values to lowercase strings, enabling case-insensitive matching.

Remarks

Evaluation Behavior:

• If false (default): Blank cells evaluate to FALSE (fail the condition test)
• If true: Blank cells evaluate to TRUE (pass the condition test)

Why This Matters:

Different consumers interpret condition results differently:

DataValidation (acts on FALSE = invalid):

• includeBlanks: false → Blanks FAIL validation (are invalid/rejected)
• includeBlanks: true → Blanks PASS validation (are valid/allowed)
• Example: "Allow dates, ignore blanks" needs includeBlanks: true so blank cells are allowed

ConditionalFormat & TableFilter (act on TRUE = show/format):

• includeBlanks: false → Blanks are NOT formatted/shown (natural behavior)
• includeBlanks: true → Blanks ARE formatted/shown (rarely needed)
• Example: "Highlight dates" with includeBlanks: false correctly excludes blanks

One policy, three readings:

A blank cell is not a value, so no operator is asked about one: this flag alone says whether it passes, at the top of a condition and inside a combinator alike. An editor shows it as one checkbox worded for its host: "Ignore blanks" for a validation, "Show blank rows" for a filter, "Format blanks" for a format.

What is blank:

• Filters and ConditionalFormat: an empty cell, a "" result, or a string of only spaces (Excel's LEN(TRIM(x))=0). A tab, a non-breaking space, 0 and an error are values.
• DataValidation: an empty cell only. A "" result is a value and is judged.

Remarks

Advisory, and what an editor asks before it saves: the rules are the ones Excel's dialogs refuse on. A condition read from a file is kept and evaluated whatever this answers; a comparison missing an operand evaluates as inert rather than as wrong.