diff --git a/lib/helper/coverage.js b/lib/helper/coverage.js
index 22ae36b..d0e6186 100644
--- a/lib/helper/coverage.js
+++ b/lib/helper/coverage.js
@@ -30,6 +30,7 @@ module.exports = wd => {
     let {
       coverageIgnore = program.coverageIgnore,
       keys = [],
+      coverageHandler,
     } = opts;
     const tempDir = path.join(cwd, 'coverage', '.temp');
     _.mkdir(tempDir);
@@ -57,7 +58,11 @@ module.exports = wd => {
           const coverage = await this.execute(`return window.__coverage__['${keys[i]}']`);
           if (coverage) {
             const coverageJSON = JSON.stringify(coverage);
-            writer.write(`"${keys[i]}":${coverageJSON}`);
+            let covChunk;
+            if (coverageHandler) {
+              covChunk = await coverageHandler(keys[i], coverageJSON);
+            }
+            writer.write(covChunk || `"${keys[i]}":${coverageJSON}`);
             if (i < keys.length - 1) {
               writer.write(',');
             }
diff --git a/package.json b/package.json
index 2efae5a..6b5fb6f 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "macaca-wd",
-  "version": "4.3.5",
+  "version": "4.3.6",
   "description": "Macaca webdirver API for Node.js",
   "keywords": [
     "macaca",