fix: axios param serializer to comply with RFC 3986 (#1180)

## Issue

**Fixes**: GetStream/stream-chat-react-native#2235

On iOS 17, all the `get` requests which involve object or array in url params (e.g. `queryMembers`) are failing.
In iOS 17, NSURLs are now encoded according to RFC 3986 standards (as specified in https://www.ietf.org/rfc/rfc3986.txt), whereas they used to adhere to RFC 1738/1808 standards in earlier versions.

reference: https://developer.apple.com/documentation/foundation/nsurl/1572047-urlwithstring
> For apps linked on or after iOS 17 and aligned OS versions, [NSURL](https://developer.apple.com/documentation/foundation/nsurl) parsing has updated from the obsolete RFC 1738/1808 parsing to the same [RFC 3986](https://www.ietf.org/rfc/rfc3986.txt) parsing as [NSURLComponents](https://developer.apple.com/documentation/foundation/nsurlcomponents). This unifies the parsing behaviors of the NSURL and NSURLComponents APIs. Now, NSURL automatically percent- and IDNA-encodes invalid characters to help create a valid URL.

And axios on the other hand doesn't adhere to RFC 3986 - it doesn't encode brackets such as `[`, `{` etc ([source](https://github.com/axios/axios/blob/v1.x/lib/helpers/buildURL.js#L20)). As a result of this, whenever `NSUrl` encounters a reserved character, such as `[`, the parser will percent encode all possible characters in the URL, including %. And this results into double encoded url, which doesn't pass the validation on Stream backend. E.g.,

```
payload=%257B%2522type%2522:%2522messaging%2522,%2522id%2522:%2522campaign-test-channel-0%2522,%2522sort%2522:%5B%5D,%2522filter_conditions%2522:%257B%2522name%2522:%2522Robert%2522%257D%257D
```

And this is a known issue with axios - axios/axios#4432

React Native tried handling this issue here - but later they reverted the fix for some other reason:
- facebook/react-native@9841bd8
- reverted facebook/react-native@2be409f


## Solution

So we need to override default param serialization of axios, and make sure that the url param string is RFC 3986 compliant

- if param is object or array, simply stringify it and then encode it.
- for the rest, do a normal uri encoding

src/client.ts

@@ -14,6 +14,7 @@ import { WSConnectionFallback } from './connection_fallback';
 import { isErrorResponse, isWSFailure } from './errors';
 import {
   addFileToFormData,
+  axiosParamsSerializer,
   chatCodes,
   isFunction,
   isOnline,
@@ -305,6 +306,8 @@ export class StreamChat<StreamChatGenerics extends ExtendableGenerics = DefaultG
     this.defaultWSTimeoutWithFallback = 6000;
     this.defaultWSTimeout = 15000;
 
+    this.axiosInstance.defaults.paramsSerializer = axiosParamsSerializer;
+
     /**
      * logger function should accept 3 parameters:
      * @param logLevel string

src/utils.ts

@@ -1,5 +1,6 @@
 import FormData from 'form-data';
 import { AscDesc, ExtendableGenerics, DefaultGenerics, OwnUserBase, OwnUserResponse, UserResponse } from './types';
+import { AxiosRequestConfig } from 'axios';
 
 /**
  * logChatPromiseExecution - utility function for logging the execution of a promise..
@@ -245,3 +246,16 @@ export function removeConnectionEventListeners(cb: (e: Event) => void) {
     window.removeEventListener('online', cb);
   }
 }
+
+export const axiosParamsSerializer: AxiosRequestConfig['paramsSerializer'] = (params) => {
+  const newParams = [];
+  for (const k in params) {
+    if (Array.isArray(params[k]) || typeof params[k] === 'object') {
+      newParams.push(`${k}=${encodeURIComponent(JSON.stringify(params[k]))}`);
+    } else {
+      newParams.push(`${k}=${encodeURIComponent(params[k])}`);
+    }
+  }
+
+  return newParams.join('&');
+};

test/unit/utils.js

@@ -1,5 +1,5 @@
 import chai from 'chai';
-import { generateUUIDv4, normalizeQuerySort } from '../../src/utils';
+import { axiosParamsSerializer, generateUUIDv4, normalizeQuerySort } from '../../src/utils';
 import sinon from 'sinon';
 
 const expect = chai.expect;
@@ -69,3 +69,32 @@ describe('test if sort is deterministic', () => {
 		expect(sort[3].direction).to.be.equal(-1);
 	});
 });
+
+describe.only('axiosParamsSerializer', () => {
+	const testCases = [
+		{
+			input: {
+				a: 1,
+				b: 2,
+				c: null,
+			},
+			output: 'a=1&b=2&c=null',
+		},
+		{
+			input: {
+				a: {
+					b: 1,
+					c: 2,
+					d: null,
+				},
+				b: [1, 2, 3],
+			},
+			output: 'a=%7B%22b%22%3A1%2C%22c%22%3A2%2C%22d%22%3Anull%7D&b=%5B1%2C2%2C3%5D',
+		},
+	];
+	it('should serialize params', () => {
+		for (const { input, output } of testCases) {
+			expect(axiosParamsSerializer(input)).to.equal(output);
+		}
+	});
+});