LESS - Guard Logical Operators



You can use the and keyword to work around logical operators with guards. You can combine the guard conditions using the and keyword and negate the conditions using the not keyword.


The following example demonstrates the use of guard logical operators in the LESS file −

<!doctype html>
      <title>Guard Logical Operators</title>
      <link rel = "stylesheet" href = "style.css" type = "text/css" />

      <h2>Example of Guard Logical Operators</h2>
      <p class = "class1">Hello World...</p>
      <p class = "class2">Welcome to Tutorialspoint...</p>

Next, create the style.less file.


.mixin (@a) when (@a > 50%) and (@a > 5px) {
   font-size: 14px;

.mixin (@a) when not (@a < 50%) and not (@a < 5px) {
   font-size: 20px;
.mixin (@a) {
   color: @a;

.class1 { .mixin(#FF0000) }
.class2 { .mixin(#555) }

You can compile the style.less to style.css by using the following command −

lessc style.less style.css

Execute the above command; it will create the style.css file automatically with the following code −


.class1 {
   font-size: 20px;
   color: #FF0000;

.class2 {
   font-size: 20px;
   color: #555;


Follow these steps to see how the above code works −

  • Save the above html code in the guard_logical_operators.html file.

  • Open this HTML file in a browser, the following output will get displayed.

Mixin Guards