fix: circular reference, close #181

Author: Scrum

src/index.js

@@ -1,40 +1,47 @@
 import postcss from 'postcss';
 
 function hasVar(str) {
-	return str.includes('var(');
+    return str.includes('var(');
 }
 
 function resolveValue(value, maps) {
-	return hasVar(value) ? value.replace(/var\(--.*?\)/g, match => maps[match.slice(4, -1)] || match) : value;
+    return hasVar(value) ? value.replace(/var\(--.*?\)/g, match => maps[match.slice(4, -1)] || match) : value;
 }
 
 function getProperty(nodes) {
-	let propertys = {};
+    let propertys = {};
 
-	nodes.walkRules(rule => {
-		if (rule.selector !== ':root') {
-			return;
-		}
+    nodes.walkRules(rule => {
+        if (rule.selector !== ':root') {
+            return;
+        }
 
-		rule.each(({prop, value}) => {
-			propertys[prop] = value;
-		});
-	});
+        rule.each(({prop, value}) => {
+            propertys[prop] = value;
+        });
+    });
 
-	return propertys;
+    return propertys;
+}
+
+function circularReference(maps) {
+    return Object.keys(maps).reduce((prevMaps, property) => {
+        prevMaps[property] = resolveValue(maps[property], maps);
+        return prevMaps;
+    }, maps);
 }
 
 export default postcss.plugin('postcss-at-rules-variables', (options = {}) => {
-	options = {
-		atRules: [...new Set(['for', 'if', 'else', 'each', 'mixin', 'custom-media', ...options.atRules || ''])],
-		variables: options.variables || {}
-	};
-
-	return nodes => {
-		const maps = Object.assign(getProperty(nodes), options.variables);
-
-		nodes.walkAtRules(new RegExp(options.atRules.join('|')), rules => {
-			rules.params = resolveValue(rules.params, maps);
-		});
-	};
+    options = {
+        atRules: [...new Set(['for', 'if', 'else', 'each', 'mixin', 'custom-media', ...options.atRules || ''])],
+        variables: options.variables || {}
+    };
+
+    return nodes => {
+        const maps = circularReference(Object.assign(getProperty(nodes), options.variables));
+
+        nodes.walkAtRules(new RegExp(options.atRules.join('|')), rules => {
+            rules.params = resolveValue(rules.params, maps);
+        });
+    };
 });