Media queries in less with variables-need global variables - css

Question

I am looking for a solution where I define 1 variable globally and than overwrite it inside a media query - without putting the entire code in it (like LESS CSS set variables in media query?).
I thought something like that(defining):
#media (min-width: 768px) {
#BWInputHeight: 40px;
}
#media (max-width: 768px) {
//responsive screens
#BWInputHeight: 20px;
}
And using it like that:
.dataTables_filter input {
.form-control;
max-width: 135px;
display: inline-block;
height: #BWInputHeight;
padding: 1px 6px;
margin-right: 15px;
}
The problem here, "#BWInputHeight" is a undeclared variable. How can I solve this with LESS ?

Answer 1

You can sort of achieve this by using list arrays for each property and screen-width (like the below sample):
#BWInputHeight: '20px','40px','60px'; // Height of the button for min-width=320 and min-width=768 respectively
#minwidths: '320px','768px','1024px'; // The widths for which you need the media queries to be created
.loop-column(#index) when (#index > 0) { // Loop to iterate through each value in #minwidths and form the corresponding output
.loop-column(#index - 1);
#width: extract(#minwidths, #index); // extracts width based on array index
#media (min-width: e(#width)){
.dataTables_filter input{
height: e(extract(#BWInputHeight,#index)); // extracts button height for the corresponding screen width
max-width: 135px;
display: inline-block;
padding: 1px 6px;
margin-right: 15px;
}
}
}
.loop-column(length(#minwidths)); // calling the function
Demo in Code-pen - Modify output area width to see difference and click the eye icon in CSS tab to see compiled CSS.
Note: As per this Stack Overflow thread, both dotless and less.js should be 99% compatible and hence I have given this answer. In case this doesn't work for you, I will happily have this answer removed.