Google spreadsheet : impose formatting within constructed string in a cell

Question

I want to be able to impose the formatting of a string that is part of a string concatenation within a cell formula, ideally depending on the value of another cell. Something like :

="This is " & FORMATSTRING(IF(A1,"bold", "normal"),"bold text")

Can I do this in Google sheets ? If yes, how ?

Answer 1

That cannot be done with a custom function, because custom functions cannot format cells. They can only return a value or an array of values that is used when evaluating the formula they are part of.

You can format cells, but not partial cell contents, with a conditional formatting custom formula rule custom formula rule like this:

=$A1

To format partial cell contents programmatically, you need a script such as formatText.

Answer 2

It is not very easy but it can be done without a script, taking advantage of the very high unicode code like 119808 for a bold A. See this test sheet