flow like the river

VISUALIZACION/node_modules/polished/lib/mixins/retinaImage.js

@@ -0,0 +1,59 @@
+"use strict";
+
+exports.__esModule = true;
+exports["default"] = retinaImage;
+var _hiDPI = _interopRequireDefault(require("./hiDPI"));
+var _errors = _interopRequireDefault(require("../internalHelpers/_errors"));
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { "default": obj }; }
+function _extends() { _extends = Object.assign ? Object.assign.bind() : function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; }; return _extends.apply(this, arguments); }
+/**
+ * A helper to generate a retina background image and non-retina
+ * background image. The retina background image will output to a HiDPI media query. The mixin uses
+ * a _2x.png filename suffix by default.
+ *
+ * @example
+ * // Styles as object usage
+ * const styles = {
+ *  ...retinaImage('my-img')
+ * }
+ *
+ * // styled-components usage
+ * const div = styled.div`
+ *   ${retinaImage('my-img')}
+ * `
+ *
+ * // CSS as JS Output
+ * div {
+ *   backgroundImage: 'url(my-img.png)',
+ *   '@media only screen and (-webkit-min-device-pixel-ratio: 1.3),
+ *    only screen and (min--moz-device-pixel-ratio: 1.3),
+ *    only screen and (-o-min-device-pixel-ratio: 1.3/1),
+ *    only screen and (min-resolution: 144dpi),
+ *    only screen and (min-resolution: 1.5dppx)': {
+ *     backgroundImage: 'url(my-img_2x.png)',
+ *   }
+ * }
+ */
+function retinaImage(filename, backgroundSize, extension, retinaFilename, retinaSuffix) {
+  var _ref;
+  if (extension === void 0) {
+    extension = 'png';
+  }
+  if (retinaSuffix === void 0) {
+    retinaSuffix = '_2x';
+  }
+  if (!filename) {
+    throw new _errors["default"](58);
+  }
+  // Replace the dot at the beginning of the passed extension if one exists
+  var ext = extension.replace(/^\./, '');
+  var rFilename = retinaFilename ? retinaFilename + "." + ext : "" + filename + retinaSuffix + "." + ext;
+  return _ref = {
+    backgroundImage: "url(" + filename + "." + ext + ")"
+  }, _ref[(0, _hiDPI["default"])()] = _extends({
+    backgroundImage: "url(" + rFilename + ")"
+  }, backgroundSize ? {
+    backgroundSize: backgroundSize
+  } : {}), _ref;
+}
+module.exports = exports.default;