Add MEXC machine support

Author: thaaddeus

package-lock.json

@@ -78,7 +78,7 @@
     "debug": "^4.4.1",
     "find-my-way": "^9.3.0",
     "is-docker": "^2.2.1",
-    "tardis-dev": "^16.5.0",
+    "tardis-dev": "^16.6.0",
     "uWebSockets.js": "github:uNetworking/uWebSockets.js#v20.59.0",
     "yargs": "^17.5.1"
   },

package.json

@@ -635,6 +635,49 @@ const bitgetMapper: SubscriptionMapper = {
     })
   }
 }
+
+const mexcMapper: SubscriptionMapper = {
+  canHandle: (message: any) => {
+    return message.method === 'SUBSCRIPTION' && Array.isArray(message.params)
+  },
+
+  map: (message: any) => {
+    return message.params.map((param: string) => {
+      const separator = param.lastIndexOf('@')
+
+      return {
+        channel: separator === -1 ? param : param.slice(0, separator),
+        symbols: separator === -1 ? [] : [param.slice(separator + 1)]
+      }
+    })
+  }
+}
+
+const mexcFuturesChannelMappings: Record<string, string> = {
+  'sub.deal': 'push.deal',
+  'sub.depth': 'push.depth',
+  'sub.ticker': 'push.ticker',
+  'sub.index.price': 'push.index.price',
+  'sub.fair.price': 'push.fair.price',
+  'sub.funding.rate': 'push.funding.rate',
+  'sub.contract': 'push.contract'
+}
+
+const mexcFuturesMapper: SubscriptionMapper = {
+  canHandle: (message: any) => {
+    return mexcFuturesChannelMappings[message.method] !== undefined
+  },
+
+  map: (message: any) => {
+    return [
+      {
+        channel: mexcFuturesChannelMappings[message.method],
+        symbols: message.param?.symbol !== undefined ? [message.param.symbol] : []
+      }
+    ]
+  }
+}
+
 const coinbaseInternationalMapper: SubscriptionMapper = {
   canHandle: (message: any) => {
     return message.type === 'SUBSCRIBE'
@@ -786,6 +829,8 @@ export const subscriptionsMappers: Record<Exchange, SubscriptionMapper> = {
   'kucoin-futures': kucoinMapper,
   bitget: bitgetMapper,
   'bitget-futures': bitgetMapper,
+  mexc: mexcMapper,
+  'mexc-futures': mexcFuturesMapper,
   'coinbase-international': coinbaseInternationalMapper,
   hyperliquid: hyperliquidMapper,
   lighter: lighterMapper,

src/ws/subscriptionsmappers.ts

@@ -13,6 +13,32 @@ describe('subscriptions mappers', () => {
     ])
   })
 
+  test('maps MEXC spot subscriptions', () => {
+    const mapper = subscriptionsMappers.mexc
+    const date = new Date()
+    const message = {
+      method: 'SUBSCRIPTION',
+      params: ['spot@public.aggre.deals.v3.api.pb@10ms@BTCUSDT', 'spot@public.aggre.depth.v3.api.pb@10ms@ETHUSDT']
+    }
+
+    expect(mapper.canHandle(message, date)).toBe(true)
+    expect(mapper.map(message, date)).toEqual([
+      { channel: 'spot@public.aggre.deals.v3.api.pb@10ms', symbols: ['BTCUSDT'] },
+      { channel: 'spot@public.aggre.depth.v3.api.pb@10ms', symbols: ['ETHUSDT'] }
+    ])
+  })
+
+  test('maps MEXC futures subscriptions', () => {
+    const mapper = subscriptionsMappers['mexc-futures']
+    const date = new Date()
+
+    expect(mapper.canHandle({ method: 'sub.depth', param: { symbol: 'BTC_USDT' }, gzip: false }, date)).toBe(true)
+    expect(mapper.map({ method: 'sub.depth', param: { symbol: 'BTC_USDT' }, gzip: false }, date)).toEqual([
+      { channel: 'push.depth', symbols: ['BTC_USDT'] }
+    ])
+    expect(mapper.map({ method: 'sub.contract' }, date)).toEqual([{ channel: 'push.contract', symbols: [] }])
+  })
+
   test('maps lighter symbol-scoped subscriptions', () => {
     const mapper = subscriptionsMappers.lighter