Implement web browser socket

packages/connect/src/utils/assert.ts

@@ -0,0 +1,25 @@
+import { assert as sharedAssert } from '@0xproject/assert';
+// We need those two unused imports because they're actually used by sharedAssert which gets injected here
+// tslint:disable-next-line:no-unused-variable
+import { Schema, schemas } from '@0xproject/json-schemas';
+// tslint:disable-next-line:no-unused-variable
+import { ECSignature } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+import * as _ from 'lodash';
+
+export const assert = {
+    ...sharedAssert,
+    isOrderbookChannelSubscriptionOpts(variableName: string, subscriptionOpts: any): void {
+        sharedAssert.doesConformToSchema(
+            'subscriptionOpts',
+            subscriptionOpts,
+            schemas.relayerApiOrderbookChannelSubscribePayload,
+        );
+    },
+    isOrderbookChannelHandler(variableName: string, handler: any): void {
+        sharedAssert.isFunction(`${variableName}.onSnapshot`, _.get(handler, 'onSnapshot'));
+        sharedAssert.isFunction(`${variableName}.onUpdate`, _.get(handler, 'onUpdate'));
+        sharedAssert.isFunction(`${variableName}.onError`, _.get(handler, 'onError'));
+        sharedAssert.isFunction(`${variableName}.onClose`, _.get(handler, 'onClose'));
+    },
+};