Sass Mixin for Borders

BorderMixin.scss

@mixin border($size, $position: false) {
    @if $position == false {
        border: $size !important;
    }
    @else {
        border-#{$position}: $size !important;
    }
}

.no-border {
    @include border(0);
}
@each $position in top, right, bottom, left {
    .no-border-#{$position} {
        @include border(0, $position);
    }
    @for $i from 1 through 50 {
        @if $i % 10 == 0 {
            .border-#{$position}-#{$i} {
                @include border($i * 1px, $position);
            }
        }
    }
}