fix(api): Remove ES6 features to add support for older versions of Node

src/index.coffee

@@ -29,7 +29,7 @@ addHeaders = (opts, s, isDataQuery) ->
   opts
 
 guessService = (u) ->
-  s = (Service[k] for own k of Service when u.startsWith Service[k]?.url)
+  s = (Service[k] for own k of Service when u.indexOf(Service[k]?.url) > -1)
   return s[0] ? {}
 
 #
@@ -236,7 +236,7 @@ request = (params...) ->
   u = if typeof q is 'string' then q else getUrl q, s
   o = if typeof q is 'string' then params[1] else params[2]
   isDataQuery = false
-  if typeof q is 'string' and q.includes '/data/'
+  if typeof q is 'string' and q.indexOf('/data/') > -1
     isDataQuery = true
   else if q.flow
     isDataQuery = true

test/index.test.coffee

@@ -191,7 +191,7 @@ describe 'API', ->
     it 'adds an accept header to data queries if the service has a default format', ->
       query = nock('http://sdw-wsrest.ecb.europa.eu')
         .matchHeader('accept', (h) ->
-          h[0].includes 'application/vnd.sdmx.data+json')
+          h[0].indexOf('application/vnd.sdmx.data+json') > -1)
         .get((uri) -> uri.indexOf('EXR') > -1)
         .reply 200, 'OK'
       response =
@@ -201,7 +201,7 @@ describe 'API', ->
     it 'adds an accept header to data URLs if the service has a default format', ->
       query = nock('http://sdw-wsrest.ecb.europa.eu')
         .matchHeader('accept', (h) ->
-          h[0].includes 'application/vnd.sdmx.data+json')
+          h[0].indexOf('application/vnd.sdmx.data+json') > -1)
         .get((uri) -> uri.indexOf('EXR') > -1)
         .reply 200, 'OK'
       url = 'http://sdw-wsrest.ecb.europa.eu/service/data/EXR/A..EUR.SP00.A'
@@ -211,7 +211,7 @@ describe 'API', ->
     it 'does not overwrite the accept header passed by the client', ->
       query = nock('http://sdw-wsrest.ecb.europa.eu')
         .matchHeader('accept', (h) ->
-          h[0].includes 'application/xml')
+          h[0].indexOf('application/xml') > -1)
         .get((uri) -> uri.indexOf('EXR') > -1)
         .reply 200, 'OK'
       opts =