npm and error messages

node_modules/csso/lib/compressor/compress/atrule/keyframes.js

@@ -0,0 +1,21 @@
+module.exports = function(node) {
+    node.block.rules.each(function(ruleset) {
+        ruleset.selector.selectors.each(function(simpleselector) {
+            simpleselector.sequence.each(function(data, item) {
+                if (data.type === 'Percentage' && data.value === '100') {
+                    item.data = {
+                        type: 'Identifier',
+                        info: data.info,
+                        name: 'to'
+                    };
+                } else if (data.type === 'Identifier' && data.name === 'from') {
+                    item.data = {
+                        type: 'Percentage',
+                        info: data.info,
+                        value: '0'
+                    };
+                }
+            });
+        });
+    });
+};