Add topExchanges()

RyanZim · RyanZim · commit 7ffbea91421d · 2017-02-25T15:38:47.000-05:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -9,6 +9,7 @@ Switched to https://min-api.cryptocompare.com/
 - added: `priceMulti()`
 - added: `priceFull()`
 - added: `topPairs()`
+- added: `topExchanges()`
 
 0.0.2 / 2016-11-21
 ------------------
diff --git a/README.md b/README.md
@@ -197,6 +197,36 @@ cc.topPairs('BTC', 2)
 .catch(console.error)
 ```
 
+### `topExchanges()`
+
+Get top exchanges by volume for a currency pair.
+
+`topExchanges(fsym, tsym[, limit])`
+
+- `fsym` (String) From Symbol
+- `tsym` (String) To Symbol
+- `limit` (Number) Limit the number of exchanges you receive (default 5).
+
+```js
+const cc = require('cryptocompare')
+
+cc.topExchanges('BTC', 'USD', 2)
+.then(exchanges => {
+  console.log(exchanges)
+  // -> [ { exchange: 'Bitfinex',
+  //        fromSymbol: 'BTC',
+  //        toSymbol: 'USD',
+  //        volume24h: 35239.36701090003,
+  //        volume24hTo: 41472258.85534388 },
+  //      { exchange: 'Bitstamp',
+  //        fromSymbol: 'BTC',
+  //        toSymbol: 'USD',
+  //        volume24h: 19658.748675010014,
+  //        volume24hTo: 23047071.74260772 } ]
+})
+.catch(console.error)
+```
+
 ## License
 
 [MIT](LICENSE.md)
diff --git a/index.js b/index.js
@@ -46,10 +46,17 @@ function topPairs (fsym, limit) {
   return fetchJSON(url).then(result => result.Data)
 }
 
+function topExchanges (fsym, tsym, limit) {
+  let url = `${baseUrl}top/exchanges?fsym=${fsym}&tsym=${tsym}`
+  if (limit) url += `&limit=${limit}`
+  return fetchJSON(url).then(result => result.Data)
+}
+
 module.exports = {
   price,
   priceMulti,
   priceFull,
   priceHistorical,
-  topPairs
+  topPairs,
+  topExchanges
 }
diff --git a/test/cryptocompare.test.js b/test/cryptocompare.test.js
@@ -127,6 +127,32 @@ test("topPairs()'s limit option works", t => {
   }).catch(t.end)
 })
 
+test('topExchanges()', t => {
+  t.plan(6 * 5 + 1)
+  cc.topExchanges('BTC', 'USD').then(exchanges => {
+    let prev
+    t.equal(exchanges.length, 5, 'returns 5 pairs by default')
+    exchanges.forEach(item => {
+      t.is(typeof item.exchange, 'string', 'item.exchange is a string')
+      t.notEqual(item.exchange, prev, 'item.exchange is unique')
+      prev = item.exchange
+      t.is(typeof item.fromSymbol, 'string', 'item.fromSymbol is a string')
+      t.is(typeof item.toSymbol, 'string', 'item.toSymbol is a string')
+      t.is(typeof item.volume24h, 'number', 'item.volume24hr is a number')
+      t.is(typeof item.volume24hTo, 'number', 'item.volume24hrTo is a number')
+    })
+    t.end()
+  }).catch(t.end)
+})
+
+test("topExchanges()'s limit option works", t => {
+  t.plan(1)
+  cc.topExchanges('BTC', 'USD', 3).then(exchanges => {
+    t.equal(exchanges.length, 3, 'limit works')
+    t.end()
+  }).catch(t.end)
+})
+
 test('error handling', t => {
   cc.price('BTC').then(prices => {
     t.end('Promise should not resolve')
