Add units to a less variable

Question

If I have a numerical LESS variable for line-height

@lineHeight: 1.2

how do I add em to the end of it to set the height of the element to produce:

height: 1.2em;

The following do not work:

height: @(lineHeight)em;
height: @(lineHeight)"em";
height: @(lineHeight) + "em";
height: @lineHeight + "em";

I have seen other threads where the answer is adding a unit is not easy, but that doesn't seem right as the numerical line-height value goes hand in hand with the em unit.

Answer 1

I found a solution in a shopware theme-mixin

 height: ~"@{lineHeight}px";

But the solution from seven-phases-max in your comments works too

 height: unit(@lineHeight, px);