Replace lodash.flatten with a small function

package.json

@@ -42,7 +42,6 @@
     "html-escaper": "^2.0.2",
     "is-plain-object": "^5.0.0",
     "lodash.debounce": "^4.0.8",
-    "lodash.flatten": "^4.4.0",
     "lodash.invokemap": "^4.6.0",
     "lodash.pullall": "^4.2.0",
     "lodash.uniqby": "^4.7.0",

src/analyzer.js

@@ -4,7 +4,6 @@ const path = require('path');
 const pullAll = require('lodash.pullall');
 const invokeMap = require('lodash.invokemap');
 const uniqBy = require('lodash.uniqby');
-const flatten = require('lodash.flatten');
 
 const gzipSize = require('gzip-size');
 const {parseChunked} = require('@discoveryjs/json-ext');
@@ -239,3 +238,34 @@ function getChunkToInitialByEntrypoint(bundleStats) {
   });
   return chunkToEntrypointInititalMap;
 };
+
+/**
+ * arr-flatten <https://github.com/jonschlinkert/arr-flatten>
+ *
+ * Copyright (c) 2014-2017, Jon Schlinkert.
+ * Released under the MIT License.
+ *
+ * Modified by Sukka <https://skk.moe>
+ *
+ * Replace recursively flatten with one-level deep flatten to match lodash.flatten
+ *
+ * TODO: replace with Array.prototype.flat once Node.js 10 support is dropped
+ */
+function flatten(arr) {
+  if (!arr) return [];
+  const len = arr.length;
+  if (!len) return [];
+
+  let cur;
+
+  const res = [];
+  for (let i = 0; i < len; i++) {
+    cur = arr[i];
+    if (Array.isArray(cur)) {
+      res.push(...cur);
+    } else {
+      res.push(cur);
+    }
+  }
+  return res;
+}