refactor: migrate to postcss 8, close #202

Author: Scrum

src/index.js

@@ -1,5 +1,3 @@
-import postcss from 'postcss';
-
 function hasVar(string) {
   return string.includes('var(');
 }
@@ -8,42 +6,40 @@ function resolveValue(value, maps) {
   return hasVar(value) ? value.replace(/var\(--.*?\)/g, match => maps[match.slice(4, -1)] || match) : value;
 }
 
-function getProperty(nodes) {
-  let propertys = {};
-
-  nodes.walkRules(rule => {
-    if (rule.selector !== ':root') {
-      return;
-    }
-
-    rule.each(({type, prop: property, value}) => {
-      if (type === 'decl') {
-        propertys[property] = value;
-      }
-    });
-  });
-
-  return propertys;
-}
-
 function circularReference(maps) {
   return Object.keys(maps).reduce((previousMaps, property) => {
     previousMaps[property] = resolveValue(maps[property], maps);
     return previousMaps;
   }, maps);
 }
 
-export default postcss.plugin('postcss-at-rules-variables', (options = {}) => {
+export default (options = {}) => {
   options = {
     atRules: [...new Set(['for', 'if', 'else', 'each', 'mixin', 'custom-media', ...options.atRules || ''])],
-    variables: options.variables || {}
+    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);
-    });
+  return {
+    postcssPlugin: 'postcss-at-rules-variables',
+    prepare() {
+      let variables = {};
+      return {
+        Declaration(node) {
+          if (node.variable) {
+            variables[node.prop] = node.value;
+          }
+        },
+        Once() {
+          variables = circularReference(Object.assign(variables, options.variables));
+        },
+        AtRule(rule) {
+          if (options.atRules.includes(rule.name)) {
+            rule.params = resolveValue(rule.params, variables);
+          }
+        }
+      };
+    }
   };
-});
+};
+
+export const postcss = true;