fix(package): In $input.path, if payload is empty, treat it as empty …

…object

index.js

@@ -24,8 +24,12 @@ module.exports = function(parameters) {
       _payload: payload.toString(),
       path: function(path) {
         var obj;
-        // if payload starts with `{` or `[` or `"`, treat as JSON
-        if (/^\s*(?:{|\[|")/.test(this._payload)) {
+        if (this._payload === '') {
+          // if payload is empty, treat it as empty object
+          //   https://github.com/ToQoz/api-gateway-mapping-template/blob/master/test/_.md#example-91575d0e
+          obj = {};
+        } else if (/^\s*(?:{|\[|")/.test(this._payload)) {
+          // if payload starts with `{` or `[` or `"`, treat as JSON
           obj = JSON.parse(this._payload);
         } else {
           // treat as string

misc/examples.js

@@ -39,6 +39,11 @@ module.exports = [
     payload: "",
     headers: {},
   },
+  {
+    template: '$input.path(\'$\')',
+    payload: "",
+    headers: {},
+  },
   {
     template: '{"name": "$input.path(\'$\')"}',
     payload: "name=toqoz",

test/_.js

@@ -68,6 +68,14 @@ describe('$input.path|$input.json', function() {
       assert.deepEqual(expected, actual);
     });
   });
+  // https://github.com/ToQoz/api-gateway-mapping-template/blob/master/test/_.md#example-91575d0e
+  describe('H=`{}` P=`` ===> T=`$input.path(\'$\')`', function() {
+    it('return ', function() {
+      var expected = {};
+      var actual = JSON.parse(mappingTemplate({template: "$input.path('$')", payload: ""}));
+      assert.deepEqual(expected, actual);
+    });
+  });
   // https://github.com/ToQoz/api-gateway-mapping-template/blob/master/test/_.md#example-25c6993c
   describe('H=`{}` P=`name=toqoz` ===> T=`{"name": "$input.path(\'$\')"}`', function() {
     it('return name=toqoz', function() {

test/_.md

@@ -38,6 +38,11 @@ Template|Header|Payload|Status code|Result
 --------|------|-------|-----------|------
 `$input.json('$')`|`None`|``|`200`|`{}`
 
+## example-91575d0e
+Template|Header|Payload|Status code|Result
+--------|------|-------|-----------|------
+`$input.path('$')`|`None`|``|`200`|`{}`
+
 ## example-25c6993c
 Template|Header|Payload|Status code|Result
 --------|------|-------|-----------|------