A LESS mixin to generate vendor-specific (browser-specific/experimental) CSS properties.

vendorify.less

.vendorify(@prop, @vals...) {
  @property: e('@{prop}');
  @values: `'@{arguments}'.replace(/^\[|\]$/g, '').split(', ').splice(1)`;

  // v1.6.0 added interpolation allowing us to do this:
  -o-@{property}: @values;
  -ms-@{property}: @values;
  -moz-@{property}: @values;
  -webkit-@{property}: @values;
  @{property}: @values;

  /*
  // If prior to v1.6.0, use this:
  -less-vendorify: ~`                         ';\n' +
    '  -o-'      + '@{property}: ' + '@{values};\n' +
    '  -ms-'     + '@{property}: ' + '@{values};\n' +
    '  -moz-'    + '@{property}: ' + '@{values};\n' +
    '  -webkit-' + '@{property}: ' + '@{values};\n' +
                 '  @{property}: ' + '@{values}'`;
  */
}

Test cases

Input

@v1:  none;                                        // display
@v2:  "✓";                                         // content
@v3:  ~"none";                                     // display
@v4:  10px;                                        // width
@v5:  1px 2px 3px 4px;                             // padding
@v6:  @v4 5px;                                     // padding
@v7:  1px solid red;                               // border
@v8:  translate(10px, 10px);                       // transform
@v9:  scale(.5) translate(10px, 10px);             // transform
@v10: url("bg1.png");                              // background-image
@v11: url('bg1.png');                              // background-image
@v12: url(bg2.png) repeat, url(bg3.png) no-repeat; // background

.test-empty              { /* at least one param required: .vendorify(); */ }
.test-prop-no-val        { .vendorify(color); }
.test-simple             { .vendorify(display, @v1); }
.test-simple-as-string   { .vendorify(content, @v2); }
.test-simple-escaped     { .vendorify(display, @v3); }
.test-px                 { .vendorify(padding, @v4); }
.test-px-several         { .vendorify(padding, @v5); }
.test-px-nested          { .vendorify(padding, @v6); }
.test-mixed-type         { .vendorify(border, @v7); }
.test-complex            { .vendorify(transform, @v8); }
.test-complex-several    { .vendorify(color, @v9); }
.test-quoted-double      { .vendorify(background-image, @v10); }
.test-quoted-single      { /* singlue quotes not allowed: .vendorify(background-image, @v11); */ }
.test-compound           { .vendorify(background, @v12); }
.test-compound-several   { .vendorify(background, @v10, @v12); }

Output

.test-empty {
  /* at least one param required: .vendorify(); */
}
.test-prop-no-val {
  -o-color: ;
  -ms-color: ;
  -moz-color: ;
  -webkit-color: ;
  color: ;
}
.test-simple {
  -o-display: none;
  -ms-display: none;
  -moz-display: none;
  -webkit-display: none;
  display: none;
}
.test-simple-as-string {
  -o-content: "✓";
  -ms-content: "✓";
  -moz-content: "✓";
  -webkit-content: "✓";
  content: "✓";
}
.test-simple-escaped {
  -o-display: none;
  -ms-display: none;
  -moz-display: none;
  -webkit-display: none;
  display: none;
}
.test-px {
  -o-padding: 10px;
  -ms-padding: 10px;
  -moz-padding: 10px;
  -webkit-padding: 10px;
  padding: 10px;
}
.test-px-several {
  -o-padding: 1px 2px 3px 4px;
  -ms-padding: 1px 2px 3px 4px;
  -moz-padding: 1px 2px 3px 4px;
  -webkit-padding: 1px 2px 3px 4px;
  padding: 1px 2px 3px 4px;
}
.test-px-nested {
  -o-padding: 10px 5px;
  -ms-padding: 10px 5px;
  -moz-padding: 10px 5px;
  -webkit-padding: 10px 5px;
  padding: 10px 5px;
}
.test-mixed-type {
  -o-border: 1px solid #ff0000;
  -ms-border: 1px solid #ff0000;
  -moz-border: 1px solid #ff0000;
  -webkit-border: 1px solid #ff0000;
  border: 1px solid #ff0000;
}
.test-complex {
  -o-transform: translate(10px, 10px);
  -ms-transform: translate(10px, 10px);
  -moz-transform: translate(10px, 10px);
  -webkit-transform: translate(10px, 10px);
  transform: translate(10px, 10px);
}
.test-complex-several {
  -o-color: scale(0.5) translate(10px, 10px);
  -ms-color: scale(0.5) translate(10px, 10px);
  -moz-color: scale(0.5) translate(10px, 10px);
  -webkit-color: scale(0.5) translate(10px, 10px);
  color: scale(0.5) translate(10px, 10px);
}
.test-quoted-double {
  -o-background-image: url("bg1.png");
  -ms-background-image: url("bg1.png");
  -moz-background-image: url("bg1.png");
  -webkit-background-image: url("bg1.png");
  background-image: url("bg1.png");
}
.test-quoted-single {
  /* singlue quotes not allowed: .vendorify(background-image, @v11); */
}
.test-compound {
  -o-background: url(bg2.png) repeat, url(bg3.png) no-repeat;
  -ms-background: url(bg2.png) repeat, url(bg3.png) no-repeat;
  -moz-background: url(bg2.png) repeat, url(bg3.png) no-repeat;
  -webkit-background: url(bg2.png) repeat, url(bg3.png) no-repeat;
  background: url(bg2.png) repeat, url(bg3.png) no-repeat;
}
.test-compound-several {
  -o-background: url("bg1.png"), url(bg2.png) repeat, url(bg3.png) no-repeat;
  -ms-background: url("bg1.png"), url(bg2.png) repeat, url(bg3.png) no-repeat;
  -moz-background: url("bg1.png"), url(bg2.png) repeat, url(bg3.png) no-repeat;
  -webkit-background: url("bg1.png"), url(bg2.png) repeat, url(bg3.png) no-repeat;
  background: url("bg1.png"), url(bg2.png) repeat, url(bg3.png) no-repeat;
}

"A useless (but harmless) -less-vendorify: ; property is included in the style definition"

Why?

Because of the way LESS works, we are unable to simply print out the string generated by the JavaScript code without it being "attached" to an existing property. We get around this by creating the bogus -less-vendorify property (it can be anything), and tricking LESS by assigning the remaining properties as the value of this property. However, we insert semicolons and line breaks so that other properties get created as well.

If you know of a way around this, I'm all ears!