[FIX] CSS var assignment only for less to less vars (#116)

lib/plugin/css-variables-pointer.js

@@ -62,9 +62,24 @@ CSSVariablesPointerPlugin.prototype = {
 		return node;
 	},
 
+	_isVariableAssignment(rule) {
+		// determines a simple less variable assignment:
+		// Rule > Value => Array[length=1] > Expression => Array[length=1] > Variable
+		const value = rule && rule.variable &&
+			rule.value instanceof less.tree.Value && rule.value;
+		const expression = value &&
+			Array.isArray(value.value) && value.value.length == 1 &&
+			value.value[0] instanceof less.tree.Expression && value.value[0];
+		const variable = expression &&
+			Array.isArray(expression.value) && expression.value.length == 1 &&
+			expression.value[0] instanceof less.tree.Variable && expression.value[0];
+		return variable;
+	},
+
 	visitVariable(node, visitArgs) {
-		// collect less variables to css variables mapping
-		if (this.callStack.length == 0 && this.ruleStack.length > 0 && this.ruleStack[this.ruleStack.length - 1].variable) {
+		// collect all simple less variables to less variables mapping (to convert them to css variables assignments)
+		if (this.callStack.length == 0 && this.ruleStack.length > 0 &&
+			this._isVariableAssignment(this.ruleStack[this.ruleStack.length - 1])) {
 			this.mVars["--" + this.ruleStack[0].name.substr(1)] = "var(" + node.name.replace(/^@/, "--") + ")";
 		}
 		return node;

test/expected/complex/test-cssvars-variables.css

@@ -1,6 +1,7 @@
 :root {
   --link-color: #428bca;
   --link-color-hover: #3071a9;
+  --other-var: 0 0 0.25rem 0 rgba(0, 0, 0, 0.15), inset 0 -0.0625rem 0 0 #428bca;
   --link-color-active: var(--link-color);
   --var: var(--a);
   --a: 9%;

test/fixtures/complex/test.less

@@ -1,6 +1,7 @@
 // Variables
 @link-color:        #428bca; // sea blue
 @link-color-hover:  darken(@link-color, 10%);
+@other-var: 0 0 0.25rem 0 rgba(0, 0, 0, 0.15), inset 0 -0.0625rem 0 0 @link-color;
 @link-color-active: @link-color;
 
 // Usage