When building Office add‑ins for PowerPoint, it is common to style only part of a table cell (e.g., to colour a single word). The TableCellProperties interface allows specifying multiple text runs when the table is created: the documentation states that if only part of a cell requires different formatting, developers should use the textRuns property . However, after a table has been created there is no supported way to change those text runs.
Today developers can enumerate cell.textRuns and read their text and font properties, but they cannot modify them: setting run.font.color or other attributes is ignored. There is also no method to replace the existing runs. This limitation is documented in Office.js issue #6129, where the expected behaviour is to have writeable textRuns so add‑ins can update per‑run formatting; the current behaviour is that textRuns in table cells are effectively read‑only and there is no “replace cell content with these textRuns” API . Attempts to recolour a run using code such as run.font.color = "#FF0000"; have no effect .
Because of this limitation, developers cannot update part of a cell’s text or change its formatting without reconstructing the entire table via specificCellProperties, which is inefficient. Please add an API to modify existing text runs or assign a new array of TextRun objects to a table cell (for example, a method like cell.setTextRuns(newTextRuns) or by making TextRun.font properties writeable). This would align table behaviour with the ability to edit a PowerPoint.TextRange on a slide and would enable dynamic updates to partial text formatting.
For completeness, the related GitHub issue #6130 notes that properties such as cell.fill.color and cell.borders.*.color are currently unavailable, which makes it difficult to reconstruct a table while preserving its colours. Addressing both text run editing and proper exposure of cell formatting would greatly improve the PowerPoint add‑ins API.