function getBordersSize(styles) {
        var positions = [];
        for (var _i = 1; _i < arguments.length; _i++) {
            positions[_i - 1] = arguments[_i];
        }
        return positions.reduce(function (size, position) {
            var value = styles['border-' + position + '-width'];
            return size + toFloat(value);
        }, 0);
    }
Extracts borders size from provided styles.

@param {CSSStyleDeclaration} styles
@param {...string} positions - Borders positions (top, right, ...)
@returns {number}