Added new "leaveUnmatchedPlaceholders" option

README.md

@@ -19,6 +19,28 @@ In browser:
 var template2 = new UriTemplate("/prefix/{?params*}");
 ```
 
+## Configuration
+You can provide a configuration object as the second argument:
+```javascript
+new UriTemplate("/prefix/{?params*}", {
+	leaveUnmatchedPlaceholders: true
+});
+```
+
+`leaveUnmatchedPlaceholders` defaults to `false`. When `true` any placeholders which do not have a corresponding key in the object, or their value is `null`, will be left in the built URL.
+
+E.g.
+```javascript
+var template = new UriTemplate("/prefix/{a}?arg1={arg1Value}", {
+	leaveUnmatchedPlaceholders: true
+});
+
+console.log(template.fill({
+	a: "something"
+}));
+```
+will output "/prefix/something?arg1={arg1Value}".
+
 ## Substitution using an object
 ```javascript
 // "/categories/green/round/"

test/custom-tests.js

@@ -2,41 +2,41 @@ var UriTemplate = require('../uri-templates');
 var assert = require('proclaim');
 
 describe("Guessing variable priority", function () {
-	it('GitHub issue #8', function () {
-		var template = new UriTemplate("{+path}/c/capture{/date,id,page}");
-		var guess = template.fromUri('/a/b/c/capture/20140101/1');
-
-		// we already test elsewhere that this reconstructs correctly - we just want to make sure variables are prioritised left-to-right
-		assert.strictEqual(guess.date, '20140101');
-		assert.strictEqual(guess.id, '1');
-		assert.strictEqual(guess.page, undefined);
-	})
+    it('GitHub issue #8', function () {
+        var template = new UriTemplate("{+path}/c/capture{/date,id,page}");
+        var guess = template.fromUri('/a/b/c/capture/20140101/1');
+
+        // we already test elsewhere that this reconstructs correctly - we just want to make sure variables are prioritised left-to-right
+        assert.strictEqual(guess.date, '20140101');
+        assert.strictEqual(guess.id, '1');
+        assert.strictEqual(guess.page, undefined);
+    })
 });
 
 describe("Original string available", function () {
-	it('GitHub issue #7', function () {
-		var template = new UriTemplate("{+path}/c/capture{/date,id,page}");
+    it('GitHub issue #7', function () {
+        var template = new UriTemplate("{+path}/c/capture{/date,id,page}");
 
-		assert.strictEqual(template.template, '{+path}/c/capture{/date,id,page}');
-		assert.strictEqual(template + "", '{+path}/c/capture{/date,id,page}');
-	})
+        assert.strictEqual(template.template, '{+path}/c/capture{/date,id,page}');
+        assert.strictEqual(template + "", '{+path}/c/capture{/date,id,page}');
+    })
 });
 
 describe("Query optional when decoding", function () {
-	it('GitHub issue #12', function () {
-		var template = new UriTemplate("{/type,ids,field}{?query*}");
+    it('GitHub issue #12', function () {
+        var template = new UriTemplate("{/type,ids,field}{?query*}");
 
-		var uri = '/user/1,2,3/posts';
-		var guess = template.fromUri(uri);
-		assert.isObject(guess);
+        var uri = '/user/1,2,3/posts';
+        var guess = template.fromUri(uri);
+        assert.isObject(guess);
 
-		var trimmed = template.fill(guess).replace(/\?$/, '');
-		assert.strictEqual(trimmed, uri);
-	});
+        var trimmed = template.fill(guess).replace(/\?$/, '');
+        assert.strictEqual(trimmed, uri);
+    });
 });
 
 describe("Decode empty query", function () {
-	it('Must return a empty object', function () {
+    it('Must return a empty object', function () {
         var template = new UriTemplate('{?query}');
 
         var uri = '?';
@@ -45,7 +45,7 @@ describe("Decode empty query", function () {
         assert.isUndefined(guess['']);
     });
 
-	it('Must return a empty object in property', function () {
+    it('Must return a empty object in property', function () {
         var template = new UriTemplate('{?query*}');
 
         var uri = '?';
@@ -54,3 +54,30 @@ describe("Decode empty query", function () {
         assert.isUndefined(guess['']);
     });
 });
+
+describe("'leaveUnmatchedPlaceholders' option enabled", function () {
+    it('Placeholder remains when property missing', function () {
+        var template = new UriTemplate('{a}/{b}{c}', {
+            leaveUnmatchedPlaceholders: true
+        });
+
+        var result = template.fill({
+            a: "1",
+            b: "2"
+        });
+        assert.strictEqual(result, "1/2{c}");
+    });
+
+     it('Placeholder remains when property is null', function () {
+        var template = new UriTemplate('{a}/{b}{c}', {
+            leaveUnmatchedPlaceholders: true
+        });
+
+        var result = template.fill({
+            a: "1",
+            b: "2",
+            c: null
+        });
+        assert.strictEqual(result, "1/2{c}");
+    });
+});

uri-templates.js

@@ -69,6 +69,7 @@
 		var varSpecMap = {};
 		for (var i = 0; i < varList.length; i++) {
 			var varName = varList[i];
+			var completeVarName = varName;
 			var truncate = null;
 			if (varName.indexOf(":") != -1) {
 				var parts = varName.split(":");
@@ -83,7 +84,8 @@
 			var varSpec = {
 				truncate: truncate,
 				name: varName,
-				suffices: suffices
+				suffices: suffices,
+				completeVarName: completeVarName
 			};
 			varSpecs.push(varSpec);
 			varSpecMap[varName] = varSpec;
@@ -96,6 +98,10 @@
 				var varSpec = varSpecs[i];
 				var value = valueFunction(varSpec.name);
 				if (value == null || (Array.isArray(value) && value.length == 0) || (typeof value == 'object' && Object.keys(value).length == 0)) {
+					if (value == null && this.options.leaveUnmatchedPlaceholders) {
+						// leave this template placeholder in the final url
+						result += "{"+varSpec.completeVarName+"}";
+					}
 					startIndex++;
 					continue;
 				}
@@ -317,7 +323,8 @@
 		};
 	}
 
-	function UriTemplate(template) {
+	function UriTemplate(template, options) {
+		options = options || {};
 		if (!(this instanceof UriTemplate)) {
 			return new UriTemplate(template);
 		}
@@ -349,7 +356,7 @@
 			var result = textParts[0];
 			for (var i = 0; i < substitutions.length; i++) {
 				var substitution = substitutions[i];
-				result += substitution(valueFunction);
+				result += substitution.call(this, valueFunction);
 				result += textParts[i + 1];
 			}
 			return result;
@@ -405,6 +412,7 @@
 		}
 		this.varNames = varNames;
 		this.template = template;
+		this.options = options;
 	}
 	UriTemplate.prototype = {
 		toString: function () {