diff --git a/README.md b/README.md
index 8fb45f6..8b105a2 100644
--- a/README.md
+++ b/README.md
@@ -5,26 +5,25 @@ starcoin.js is a full featured sdk for developing dapp on [Starcoin](https://git
 [Type Architecture Diagram](./src/lib/README.md)
 
 ## Docs
+
 [Starcoin Javascript SDK](https://starcoin.org/zh/developer/sdk/javascript/)
 
 ## Usage
 
 First, start a Starcoin node with websocket and http APIs opened.
 
-``` shell
+```shell
 ./starcoin -n dev --miner-thread 4 --websocket-apis all --http-apis all
 ```
 
 or
 
-
-``` shell
+```shell
 ./starcoin -n barnard --miner-thread 4 --websocket-apis all --http-apis all
 ```
 
-
-``` typescript
-let provider = new JsonRpcProvider("http://localhost:9850");
+```typescript
+let provider = new JsonRpcProvider('http://localhost:9850');
 
 /// Get txn data.
 const txnData = await provider.getTransaction(txnHash);
@@ -33,14 +32,18 @@ const txnInfoData = await provider.getTransactionInfo(txnHash);
 /// Send Transaction
 
 let signer = provider.getSigner();
-await signer.unlock(""); // put password into the quotes
+await signer.unlock(''); // put password into the quotes
 // starcoin node should enable account jsonrpc api.
 const txnRequest = {
-    script: {
-      code: '0x1::TransferScripts::peer_to_peer',
-      type_args: ['0x1::STC::STC'],
-      args: ['0xc13b50bdb12e3fdd03c4e3b05e34926a', 'x"29b6012aee31a216af67c3d05e21a092c13b50bdb12e3fdd03c4e3b05e34926a"', '100000u128'],
-    }
+  script: {
+    code: '0x1::TransferScripts::peer_to_peer',
+    type_args: ['0x1::STC::STC'],
+    args: [
+      '0xc13b50bdb12e3fdd03c4e3b05e34926a',
+      'x"29b6012aee31a216af67c3d05e21a092c13b50bdb12e3fdd03c4e3b05e34926a"',
+      '100000u128',
+    ],
+  },
 };
 let txn = await signer.sendTransaction(txnRequest);
 // wait for 7 confirmations.
@@ -59,7 +62,7 @@ client sdk should decode the data to see the detailed information.
 import encoding from 'starcoin';
 import 'starcoin';
 
-let provider = new JsonRpcProvider("http://localhost:9850");
+let provider = new JsonRpcProvider('http://localhost:9850');
 
 // Get txn info.
 const txnEvents = await provider.getEventsOfTransaction(txnHash);
@@ -87,10 +90,81 @@ You can also see the spec in `src/index.spec.ts`.
 
 3. `npm login`
 
-4. `npm config set registry https://registry.npmjs.org/`  # use `npm config ls` to confirm
+4. `npm config set registry https://registry.npmjs.org/` # use `npm config ls` to confirm
 
 5. `npm publish --access public --tag latest --dry-run` # test locally before actually publishing to the registry
 
 6. `npm publish --access public --tag latest`
 
-Welcome for your PRs! 
+## FAQ
+
+### `Uncaught TypeError: Cannot convert a BigInt value to a number` in create-react-app
+
+If you are using this sdk in your dapp build up by create-react-app, and sdk version >= 2.0.0,
+you will get following error in production(`yarn build`), which is not happen in developement(`yarn start`):
+
+`Uncaught TypeError: Cannot convert a BigInt value to a number`
+
+1. Root cause:
+
+The plugin @babel/plugin-transform-exponentiation-operator in create-react-app will convert
+
+```
+let x = 10 ** 2;
+```
+
+into
+
+```
+let x = Math.pow(10, 2);`
+```
+
+This operation has no effect on Number, but for the BigInt type of ECMAScript 2020, this conversion is a fatal error. Math.pow() only supports Number type parameters.
+
+and the `browserslist` section in create-react-app's `package.json` is:
+
+```
+  "browserslist": {
+    "production": [
+       ">0.2%",
+       "not dead",
+       "not op_mini all"
+    ],
+    "development": [
+       "last 1 chrome version",
+       "last 1 firefox version",
+       "last 1 safari version"
+    ]
+  },
+```
+
+the production taget is too old to support ECMAScript 2020.
+
+2. Solution:
+
+1) change the `browserslist` section in your dapp's `package.json` as following:
+
+```
+  "browserslist": {
+    "production": [
+      "chrome >= 67",
+      "edge >= 79",
+      "firefox >= 68",
+      "opera >= 54",
+      "safari >= 14"
+    ],
+    "development": [
+      "chrome >= 67",
+      "edge >= 79",
+      "firefox >= 68",
+      "opera >= 54",
+      "safari >= 14"
+    ]
+  },
+```
+
+2. rm -f node_modules/.cache
+
+3. yarn build
+
+Welcome for your PRs!
