.

node_modules/cssstyle/lib/properties/backgroundPosition.js

@@ -0,0 +1,58 @@
+'use strict';
+
+var parsers = require('../parsers');
+
+var valid_keywords = ['top', 'center', 'bottom', 'left', 'right'];
+
+var parse = function parse(v) {
+  if (v === '' || v === null) {
+    return undefined;
+  }
+  var parts = v.split(/\s+/);
+  if (parts.length > 2 || parts.length < 1) {
+    return undefined;
+  }
+  var types = [];
+  parts.forEach(function(part, index) {
+    types[index] = parsers.valueType(part);
+  });
+  if (parts.length === 1) {
+    if (types[0] === parsers.TYPES.LENGTH || types[0] === parsers.TYPES.PERCENT) {
+      return v;
+    }
+    if (types[0] === parsers.TYPES.KEYWORD) {
+      if (valid_keywords.indexOf(v.toLowerCase()) !== -1 || v.toLowerCase() === 'inherit') {
+        return v;
+      }
+    }
+    return undefined;
+  }
+  if (
+    (types[0] === parsers.TYPES.LENGTH || types[0] === parsers.TYPES.PERCENT) &&
+    (types[1] === parsers.TYPES.LENGTH || types[1] === parsers.TYPES.PERCENT)
+  ) {
+    return v;
+  }
+  if (types[0] !== parsers.TYPES.KEYWORD || types[1] !== parsers.TYPES.KEYWORD) {
+    return undefined;
+  }
+  if (valid_keywords.indexOf(parts[0]) !== -1 && valid_keywords.indexOf(parts[1]) !== -1) {
+    return v;
+  }
+  return undefined;
+};
+
+module.exports.isValid = function isValid(v) {
+  return parse(v) !== undefined;
+};
+
+module.exports.definition = {
+  set: function(v) {
+    this._setProperty('background-position', parse(v));
+  },
+  get: function() {
+    return this.getPropertyValue('background-position');
+  },
+  enumerable: true,
+  configurable: true,
+};