added suggestCompression config

src/lib/host.js

@@ -34,6 +34,7 @@ function Host(config) {
   this.auth = null;
   this.query = null;
   this.headers = null;
+  this.suggestCompression = false;
 
   if (typeof config === 'string') {
     if (!startsWithProtocolRE.test(config)) {
@@ -137,7 +138,7 @@ Host.prototype.makeUrl = function (params) {
 function objectPropertyGetter(prop, preOverride) {
   return function (overrides) {
     if (preOverride) {
-      overrides = preOverride(overrides);
+      overrides = preOverride.call(this, overrides);
     }
 
     var obj = this[prop];
@@ -153,7 +154,16 @@ function objectPropertyGetter(prop, preOverride) {
   };
 }
 
-Host.prototype.getHeaders = objectPropertyGetter('headers');
+Host.prototype.getHeaders = objectPropertyGetter('headers', function (overrides) {
+  if (!this.suggestCompression) {
+    return overrides;
+  }
+
+  return _.defaults(overrides || {}, {
+    'Accept-Encoding': 'gzip,deflate'
+  });
+});
+
 Host.prototype.getQuery = objectPropertyGetter('query', function (query) {
   return typeof query === 'string' ? qs.parse(query) : query;
 });

test/unit/specs/host.js

@@ -11,7 +11,8 @@ var hostDefaults = {
   path: '',
   auth: null,
   query: {},
-  headers: null
+  headers: null,
+  suggestCompression: false
 };
 
 describe('Host class', function () {
@@ -169,4 +170,36 @@ describe('Host class', function () {
     });
   });
 
+  describe('#getHeaders', function () {
+    it('merges the passed in headers with the default headers', function () {
+      var host = new Host({ headers: { 'Joe-Smith': 'present' } });
+
+      expect(host.getHeaders({
+        'John-Smith': 'present'
+      })).to.eql({
+        'John-Smith': 'present',
+        'Joe-Smith': 'present'
+      });
+    });
+
+    it('overrides the default headers with the passed in headers', function () {
+      var host = new Host({ headers: { 'Joe-Smith': 'present' } });
+
+      expect(host.getHeaders({
+        'John-Smith': 'present',
+        'Joe-Smith': 'absent'
+      })).to.eql({
+        'John-Smith': 'present',
+        'Joe-Smith': 'absent'
+      });
+    });
+
+    it('adds Accept-Encoding header when the suggestCompression setting is true', function () {
+      var host = new Host({ suggestCompression: true });
+      expect(host.getHeaders()).to.eql({
+        'Accept-Encoding': 'gzip,deflate'
+      });
+    });
+  });
+
 });