Refactor JSON parsing in HttpClient

3 files changed, 64 insertions, 18 deletions

diff --git a/packages/connect/src/utils/orderbook_channel_message_parsers.ts b/packages/connect/src/utils/orderbook_channel_message_parser.ts
index d9a84cca2..adc565d29 100644
--- a/packages/connect/src/utils/orderbook_channel_message_parsers.ts
+++ b/packages/connect/src/utils/orderbook_channel_message_parser.ts
@@ -7,10 +7,10 @@ import {
     OrderbookChannelMessageTypes,
 } from '../types';
 
-import {typeConverters} from './type_converters';
+import {relayerResponseJsonParsers} from './relayer_response_json_parsers';
 
-export const orderbookChannelMessageParsers = {
-    parser(utf8Data: string): OrderbookChannelMessage {
+export const orderbookChannelMessageParser = {
+    parse(utf8Data: string): OrderbookChannelMessage {
         const messageObj = JSON.parse(utf8Data);
         const type: string = _.get(messageObj, 'type');
         assert.assert(!_.isUndefined(type), `Message is missing a type parameter: ${utf8Data}`);
@@ -18,15 +18,15 @@ export const orderbookChannelMessageParsers = {
         switch (type) {
             case (OrderbookChannelMessageTypes.Snapshot): {
                 assert.doesConformToSchema('message', messageObj, schemas.relayerApiOrderbookChannelSnapshotSchema);
-                const orderbook = messageObj.payload;
-                typeConverters.convertOrderbookStringFieldsToBigNumber(orderbook);
-                return messageObj;
+                const orderbookJson = messageObj.payload;
+                const orderbook = relayerResponseJsonParsers.parseOrderbookResponseJson(orderbookJson);
+                return _.assign(messageObj, {payload: orderbook});
             }
             case (OrderbookChannelMessageTypes.Update): {
                 assert.doesConformToSchema('message', messageObj, schemas.relayerApiOrderbookChannelUpdateSchema);
-                const order = messageObj.payload;
-                typeConverters.convertOrderStringFieldsToBigNumber(order);
-                return messageObj;
+                const orderJson = messageObj.payload;
+                const order = relayerResponseJsonParsers.parseOrderJson(orderJson);
+                return _.assign(messageObj, {payload: order});
             }
             default: {
                 return {
diff --git a/packages/connect/src/utils/relayer_response_json_parsers.ts b/packages/connect/src/utils/relayer_response_json_parsers.ts
new file mode 100644
index 000000000..02d88f26d
--- /dev/null
+++ b/packages/connect/src/utils/relayer_response_json_parsers.ts
@@ -0,0 +1,42 @@
+import {assert} from '@0xproject/assert';
+import {schemas} from '@0xproject/json-schemas';
+import * as _ from 'lodash';
+
+import {
+    FeesResponse,
+    OrderbookResponse,
+    SignedOrder,
+    TokenPairsItem,
+} from '../types';
+
+import {typeConverters} from './type_converters';
+
+export const relayerResponseJsonParsers = {
+    parseTokenPairsJson(json: any): TokenPairsItem[] {
+        assert.doesConformToSchema('tokenPairs', json, schemas.relayerApiTokenPairsResponseSchema);
+        return json.map((tokenPair: any) => {
+            return typeConverters.convertStringsFieldsToBigNumbers(tokenPair, [
+                'tokenA.minAmount',
+                'tokenA.maxAmount',
+                'tokenB.minAmount',
+                'tokenB.maxAmount',
+            ]);
+        });
+    },
+    parseOrdersJson(json: any): SignedOrder[] {
+        assert.doesConformToSchema('orders', json, schemas.signedOrdersSchema);
+        return json.map((order: object) => typeConverters.convertOrderStringFieldsToBigNumber(order));
+    },
+    parseOrderJson(json: any): SignedOrder {
+        assert.doesConformToSchema('order', json, schemas.signedOrderSchema);
+        return typeConverters.convertOrderStringFieldsToBigNumber(json);
+    },
+    parseOrderbookResponseJson(json: any): OrderbookResponse {
+        assert.doesConformToSchema('orderBook', json, schemas.relayerApiOrderBookResponseSchema);
+        return typeConverters.convertOrderbookStringFieldsToBigNumber(json);
+    },
+    parseFeesResponseJson(json: any): FeesResponse {
+        assert.doesConformToSchema('fees', json, schemas.relayerApiFeesResponseSchema);
+        return typeConverters.convertStringsFieldsToBigNumbers(json, ['makerFee', 'takerFee']);
+    },
+};
diff --git a/packages/connect/src/utils/type_converters.ts b/packages/connect/src/utils/type_converters.ts
index 28810af1a..5ba1b8291 100644
--- a/packages/connect/src/utils/type_converters.ts
+++ b/packages/connect/src/utils/type_converters.ts
@@ -1,15 +1,17 @@
 import {BigNumber} from 'bignumber.js';
 import * as _ from 'lodash';
 
-// TODO: convert all of these to non-mutating, pure functions
 export const typeConverters = {
-    convertOrderbookStringFieldsToBigNumber(orderbook: object): void {
-        _.each(orderbook, (orders: object[]) => {
-            _.each(orders, (order: object) => this.convertOrderStringFieldsToBigNumber(order));
-        });
+    convertOrderbookStringFieldsToBigNumber(orderbook: any): any {
+        const bids = _.get(orderbook, 'bids', []);
+        const asks = _.get(orderbook, 'asks', []);
+        return {
+            bids: bids.map((order: any) => this.convertOrderStringFieldsToBigNumber(order)),
+            asks: asks.map((order: any) => this.convertOrderStringFieldsToBigNumber(order)),
+        };
     },
-    convertOrderStringFieldsToBigNumber(order: object): void {
-        this.convertStringsFieldsToBigNumbers(order, [
+    convertOrderStringFieldsToBigNumber(order: any): any {
+        return this.convertStringsFieldsToBigNumbers(order, [
             'makerTokenAmount',
             'takerTokenAmount',
             'makerFee',
@@ -18,9 +20,11 @@ export const typeConverters = {
             'salt',
         ]);
     },
-    convertStringsFieldsToBigNumbers(obj: object, fields: string[]): void {
+    convertStringsFieldsToBigNumbers(obj: any, fields: string[]): any {
+        const result = _.assign({}, obj);
         _.each(fields, field => {
-            _.update(obj, field, (value: string) => new BigNumber(value));
+            _.update(result, field, (value: string) => new BigNumber(value));
         });
+        return result;
     },
 };