diff --git a/README.md b/README.md
index 76ceb34..4da3c34 100644
--- a/README.md
+++ b/README.md
@@ -48,7 +48,7 @@ Source.prototype.sourceAndMap(options: Object) -> {
 }
 ```
 
-Returns both, source code (like `Source.prototype.source()` and SourceMap (like `Source.prototype.map()`). This method could have better performance than calling `source()` and `map()` separatly.
+Returns both, source code (like `Source.prototype.source()` and SourceMap (like `Source.prototype.map()`). This method could have better performance than calling `source()` and `map()` separately.
 
 See `map()` for `options`.
 
diff --git a/lib/OriginalSource.js b/lib/OriginalSource.js
index 11aff07..f3b5227 100644
--- a/lib/OriginalSource.js
+++ b/lib/OriginalSource.js
@@ -41,7 +41,10 @@ class OriginalSource extends Source {
 				}
 				return new SourceNode(null, null, null,
 					_splitCode(line + (idx != lines.length - 1 ? "\n" : "")).map(function(item) {
-						if(/^\s*$/.test(item)) return item;
+						if(/^\s*$/.test(item)) {
+							pos += item.length;
+							return item;
+						}
 						var res = new SourceNode(idx + 1, pos, name, item);
 						pos += item.length;
 						return res;
diff --git a/lib/ReplaceSource.js b/lib/ReplaceSource.js
index a4b9ad8..f2f781f 100644
--- a/lib/ReplaceSource.js
+++ b/lib/ReplaceSource.js
@@ -10,24 +10,35 @@ var SourceListMap = require("source-list-map").SourceListMap;
 var fromStringWithSourceMap = require("source-list-map").fromStringWithSourceMap;
 var SourceMapConsumer = require("source-map").SourceMapConsumer;
 
+class Replacement {
+	constructor(start, end, content, insertIndex, name) {
+		this.start = start;
+		this.end = end;
+		this.content = content;
+		this.insertIndex = insertIndex;
+		this.name = name;
+	}
+}
+
 class ReplaceSource extends Source {
 	constructor(source, name) {
 		super();
 		this._source = source;
 		this._name = name;
+		/** @type {Replacement[]} */
 		this.replacements = [];
 	}
 
-	replace(start, end, newValue) {
+	replace(start, end, newValue, name) {
 		if(typeof newValue !== "string")
 			throw new Error("insertion must be a string, but is a " + typeof newValue);
-		this.replacements.push([start, end, newValue, this.replacements.length]);
+		this.replacements.push(new Replacement(start, end, newValue, this.replacements.length, name));
 	}
 
-	insert(pos, newValue) {
+	insert(pos, newValue, name) {
 		if(typeof newValue !== "string")
 			throw new Error("insertion must be a string, but is a " + typeof newValue + ": " + newValue);
-		this.replacements.push([pos, pos - 1, newValue, this.replacements.length]);
+		this.replacements.push(new Replacement(pos, pos - 1, newValue, this.replacements.length, name));
 	}
 
 	source(options) {
@@ -40,13 +51,13 @@ class ReplaceSource extends Source {
 
 	_sortReplacements() {
 		this.replacements.sort(function(a, b) {
-			var diff = b[1] - a[1];
+			var diff = b.end - a.end;
 			if(diff !== 0)
 				return diff;
-			diff = b[0] - a[0];
+			diff = b.start - a.start;
 			if(diff !== 0)
 				return diff;
-			return b[3] - a[3];
+			return b.insertIndex - a.insertIndex;
 		});
 	}
 
@@ -57,9 +68,9 @@ class ReplaceSource extends Source {
 		var result = [str];
 		this.replacements.forEach(function(repl) {
 			var remSource = result.pop();
-			var splitted1 = this._splitString(remSource, Math.floor(repl[1] + 1));
-			var splitted2 = this._splitString(splitted1[0], Math.floor(repl[0]));
-			result.push(splitted1[1], repl[2], splitted2[0]);
+			var splitted1 = this._splitString(remSource, Math.floor(repl.end + 1));
+			var splitted2 = this._splitString(splitted1[0], Math.floor(repl.start));
+			result.push(splitted1[1], repl.content, splitted2[0]);
 		}, this);
 
 		// write out result array in reverse order
@@ -146,18 +157,18 @@ class ReplaceSource extends Source {
 					removeChars = 0;
 				}
 				var finalStr = "";
-				while(idxReplacement >= 0 && replacements[idxReplacement][0] < newCurrentIndex) {
+				while(idxReplacement >= 0 && replacements[idxReplacement].start < newCurrentIndex) {
 					var repl = replacements[idxReplacement];
-					var start = Math.floor(repl[0]);
-					var end = Math.floor(repl[1] + 1);
+					var start = Math.floor(repl.start);
+					var end = Math.floor(repl.end + 1);
 					var before = str.substr(0, Math.max(0, start - currentIndex));
 					if(end <= newCurrentIndex) {
 						var after = str.substr(Math.max(0, end - currentIndex));
-						finalStr += before + repl[2];
+						finalStr += before + repl.content;
 						str = after;
 						currentIndex = Math.max(currentIndex, end);
 					} else {
-						finalStr += before + repl[2];
+						finalStr += before + repl.content;
 						str = "";
 						removeChars = end - newCurrentIndex;
 					}
@@ -170,7 +181,7 @@ class ReplaceSource extends Source {
 		});
 		var extraCode = "";
 		while(idxReplacement >= 0) {
-			extraCode += replacements[idxReplacement][2];
+			extraCode += replacements[idxReplacement].content;
 			idxReplacement--;
 		}
 		if(extraCode) {
@@ -246,7 +257,8 @@ class ReplaceSource extends Source {
 						mapping.line,
 						mapping.column,
 						mapping.source,
-						replace.value
+						replace.value,
+						mapping.name || replace.name
 					));
 				}
 			}
@@ -259,6 +271,9 @@ class ReplaceSource extends Source {
 }
 
 class ReplacementEnumerator {
+	/**
+	 * @param {Replacement[]} replacements list of replacements
+	 */
 	constructor(replacements) {
 		this.replacements = replacements || [];
 		this.index = this.replacements.length;
@@ -274,9 +289,10 @@ class ReplacementEnumerator {
 		if(this.emit) {
 			// Start point found. stop emitting. set position to find end
 			var repl = this.replacements[this.index];
-			var end = Math.floor(repl[1] + 1);
+			var end = Math.floor(repl.end + 1);
 			this.position = end;
-			this.value = repl[2];
+			this.value = repl.content;
+			this.name = repl.name;
 		} else {
 			// End point found. start emitting. set position to find next start
 			this.index--;
@@ -284,7 +300,7 @@ class ReplacementEnumerator {
 				this.done = true;
 			} else {
 				var nextRepl = this.replacements[this.index];
-				var start = Math.floor(nextRepl[0]);
+				var start = Math.floor(nextRepl.start);
 				this.position = start;
 			}
 		}
@@ -303,7 +319,9 @@ class ReplacementEnumerator {
 			var resultStr = "";
 			for(var i = this.index; i >= 0; i--) {
 				var repl = this.replacements[i];
-				resultStr += repl[2];
+				// this doesn't need to handle repl.name, because in SourceMaps generated code
+				// without pointer to original source can't have a name
+				resultStr += repl.content;
 			}
 			return resultStr;
 		}
diff --git a/package.json b/package.json
index 56f8a83..d5d3775 100644
--- a/package.json
+++ b/package.json
@@ -27,7 +27,8 @@
     "istanbul": "^0.4.1",
     "js-beautify": "^1.5.10",
     "mocha": "^3.4.2",
-    "should": "^11.2.1"
+    "should": "^11.2.1",
+    "sourcemap-validator": "^1.1.0"
   },
   "files": [
     "lib/"
diff --git a/test/ReplaceSource.js b/test/ReplaceSource.js
index d11f14f..0510337 100644
--- a/test/ReplaceSource.js
+++ b/test/ReplaceSource.js
@@ -2,6 +2,7 @@ var should = require("should");
 var ReplaceSource = require("../lib/ReplaceSource");
 var RawSource = require("../lib/RawSource");
 var OriginalSource = require("../lib/OriginalSource");
+var validate = require('sourcemap-validator');
 
 describe("ReplaceSource", function() {
 	it("should replace correctly", function() {
@@ -154,4 +155,23 @@ describe("ReplaceSource", function() {
 		resultMap.map.mappings.should.be.eql("AAAA");
 		resultListMap.map.mappings.should.be.eql("AAAA;;");
 	});
+
+	it("should produce correct source map", function() {
+		var bootstrapCode = '   var hello\n   var world\n';
+
+		should(function() {
+			var source = new ReplaceSource(new OriginalSource(bootstrapCode, "file.js"));
+			source.replace(7, 11, 'h', 'incorrect');
+			source.replace(20, 24, 'w', 'identifiers');
+			var resultMap = source.sourceAndMap();
+			validate(resultMap.source, JSON.stringify(resultMap.map));
+		}).throw();
+
+		var source = new ReplaceSource(new OriginalSource(bootstrapCode, "file.js"));
+		source.replace(7, 11, 'h', 'hello');
+		source.replace(20, 24, 'w', 'world');
+		var resultMap = source.sourceAndMap();
+		validate(resultMap.source, JSON.stringify(resultMap.map));
+
+	});
 });
diff --git a/yarn.lock b/yarn.lock
index 04a85e2..cfeb84b 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -969,6 +969,10 @@ jsbn@~0.1.0:
   version "0.1.1"
   resolved "https://registry.yarnpkg.com/jsbn/-/jsbn-0.1.1.tgz#a5e654c2e5a2deb5f201d96cefbca80c0ef2f513"
 
+jsesc@~0.3.x:
+  version "0.3.0"
+  resolved "https://registry.yarnpkg.com/jsesc/-/jsesc-0.3.0.tgz#1bf5ee63b4539fe2e26d0c1e99c240b97a457972"
+
 json-schema@0.2.3:
   version "0.2.3"
   resolved "https://registry.yarnpkg.com/json-schema/-/json-schema-0.2.3.tgz#b480c892e59a2f05954ce727bd3f2a4e882f9e13"
@@ -1032,6 +1036,14 @@ lodash._baseassign@^3.0.0:
     lodash._basecopy "^3.0.0"
     lodash.keys "^3.0.0"
 
+lodash._basebind@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._basebind/-/lodash._basebind-2.3.0.tgz#2b5bc452a0e106143b21869f233bdb587417d248"
+  dependencies:
+    lodash._basecreate "~2.3.0"
+    lodash._setbinddata "~2.3.0"
+    lodash.isobject "~2.3.0"
+
 lodash._basecopy@^3.0.0:
   version "3.0.1"
   resolved "https://registry.yarnpkg.com/lodash._basecopy/-/lodash._basecopy-3.0.1.tgz#8da0e6a876cf344c0ad8a54882111dd3c5c7ca36"
@@ -1040,14 +1052,106 @@ lodash._basecreate@^3.0.0:
   version "3.0.3"
   resolved "https://registry.yarnpkg.com/lodash._basecreate/-/lodash._basecreate-3.0.3.tgz#1bc661614daa7fc311b7d03bf16806a0213cf821"
 
+lodash._basecreate@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._basecreate/-/lodash._basecreate-2.3.0.tgz#9b88a86a4dcff7b7f3c61d83a2fcfc0671ec9de0"
+  dependencies:
+    lodash._renative "~2.3.0"
+    lodash.isobject "~2.3.0"
+    lodash.noop "~2.3.0"
+
+lodash._basecreatecallback@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._basecreatecallback/-/lodash._basecreatecallback-2.3.0.tgz#37b2ab17591a339e988db3259fcd46019d7ac362"
+  dependencies:
+    lodash._setbinddata "~2.3.0"
+    lodash.bind "~2.3.0"
+    lodash.identity "~2.3.0"
+    lodash.support "~2.3.0"
+
+lodash._basecreatewrapper@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._basecreatewrapper/-/lodash._basecreatewrapper-2.3.0.tgz#aa0c61ad96044c3933376131483a9759c3651247"
+  dependencies:
+    lodash._basecreate "~2.3.0"
+    lodash._setbinddata "~2.3.0"
+    lodash._slice "~2.3.0"
+    lodash.isobject "~2.3.0"
+
+lodash._createwrapper@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._createwrapper/-/lodash._createwrapper-2.3.0.tgz#d1aae1102dadf440e8e06fc133a6edd7fe146075"
+  dependencies:
+    lodash._basebind "~2.3.0"
+    lodash._basecreatewrapper "~2.3.0"
+    lodash.isfunction "~2.3.0"
+
+lodash._escapehtmlchar@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._escapehtmlchar/-/lodash._escapehtmlchar-2.3.0.tgz#d03da6bd82eedf38dc0a5b503d740ecd0e894592"
+  dependencies:
+    lodash._htmlescapes "~2.3.0"
+
+lodash._escapestringchar@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._escapestringchar/-/lodash._escapestringchar-2.3.0.tgz#cce73ae60fc6da55d2bf8a0679c23ca2bab149fc"
+
 lodash._getnative@^3.0.0:
   version "3.9.1"
   resolved "https://registry.yarnpkg.com/lodash._getnative/-/lodash._getnative-3.9.1.tgz#570bc7dede46d61cdcde687d65d3eecbaa3aaff5"
 
+lodash._htmlescapes@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._htmlescapes/-/lodash._htmlescapes-2.3.0.tgz#1ca98863cadf1fa1d82c84f35f31e40556a04f3a"
+
 lodash._isiterateecall@^3.0.0:
   version "3.0.9"
   resolved "https://registry.yarnpkg.com/lodash._isiterateecall/-/lodash._isiterateecall-3.0.9.tgz#5203ad7ba425fae842460e696db9cf3e6aac057c"
 
+lodash._objecttypes@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._objecttypes/-/lodash._objecttypes-2.3.0.tgz#6a3ea3987dd6eeb8021b2d5c9c303549cc2bae1e"
+
+lodash._reinterpolate@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._reinterpolate/-/lodash._reinterpolate-2.3.0.tgz#03ee9d85c0e55cbd590d71608a295bdda51128ec"
+
+lodash._renative@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._renative/-/lodash._renative-2.3.0.tgz#77d8edd4ced26dd5971f9e15a5f772e4e317fbd3"
+
+lodash._reunescapedhtml@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._reunescapedhtml/-/lodash._reunescapedhtml-2.3.0.tgz#db920b55ac7f3ff825939aceb9ba2c231713d24d"
+  dependencies:
+    lodash._htmlescapes "~2.3.0"
+    lodash.keys "~2.3.0"
+
+lodash._setbinddata@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._setbinddata/-/lodash._setbinddata-2.3.0.tgz#e5610490acd13277d59858d95b5f2727f1508f04"
+  dependencies:
+    lodash._renative "~2.3.0"
+    lodash.noop "~2.3.0"
+
+lodash._shimkeys@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._shimkeys/-/lodash._shimkeys-2.3.0.tgz#611f93149e3e6c721096b48769ef29537ada8ba9"
+  dependencies:
+    lodash._objecttypes "~2.3.0"
+
+lodash._slice@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash._slice/-/lodash._slice-2.3.0.tgz#147198132859972e4680ca29a5992c855669aa5c"
+
+lodash.bind@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.bind/-/lodash.bind-2.3.0.tgz#c2a8e18b68e5ecc152e2b168266116fea5b016cc"
+  dependencies:
+    lodash._createwrapper "~2.3.0"
+    lodash._renative "~2.3.0"
+    lodash._slice "~2.3.0"
+
 lodash.create@3.1.1:
   version "3.1.1"
   resolved "https://registry.yarnpkg.com/lodash.create/-/lodash.create-3.1.1.tgz#d7f2849f0dbda7e04682bb8cd72ab022461debe7"
@@ -1056,6 +1160,40 @@ lodash.create@3.1.1:
     lodash._basecreate "^3.0.0"
     lodash._isiterateecall "^3.0.0"
 
+lodash.defaults@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.defaults/-/lodash.defaults-2.3.0.tgz#a832b001f138f3bb9721c2819a2a7cc5ae21ed25"
+  dependencies:
+    lodash._objecttypes "~2.3.0"
+    lodash.keys "~2.3.0"
+
+lodash.escape@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.escape/-/lodash.escape-2.3.0.tgz#844c38c58f844e1362ebe96726159b62cf5f2a58"
+  dependencies:
+    lodash._escapehtmlchar "~2.3.0"
+    lodash._reunescapedhtml "~2.3.0"
+    lodash.keys "~2.3.0"
+
+lodash.foreach@~2.3.x:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.foreach/-/lodash.foreach-2.3.0.tgz#083404c91e846ee77245fdf9d76519c68b2af168"
+  dependencies:
+    lodash._basecreatecallback "~2.3.0"
+    lodash.forown "~2.3.0"
+
+lodash.forown@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.forown/-/lodash.forown-2.3.0.tgz#24fb4aaf800d45fc2dc60bfec3ce04c836a3ad7f"
+  dependencies:
+    lodash._basecreatecallback "~2.3.0"
+    lodash._objecttypes "~2.3.0"
+    lodash.keys "~2.3.0"
+
+lodash.identity@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.identity/-/lodash.identity-2.3.0.tgz#6b01a210c9485355c2a913b48b6711219a173ded"
+
 lodash.isarguments@^3.0.0:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/lodash.isarguments/-/lodash.isarguments-3.1.0.tgz#2f573d85c6a24289ff00663b491c1d338ff3458a"
@@ -1064,6 +1202,16 @@ lodash.isarray@^3.0.0:
   version "3.0.4"
   resolved "https://registry.yarnpkg.com/lodash.isarray/-/lodash.isarray-3.0.4.tgz#79e4eb88c36a8122af86f844aa9bcd851b5fbb55"
 
+lodash.isfunction@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.isfunction/-/lodash.isfunction-2.3.0.tgz#6b2973e47a647cf12e70d676aea13643706e5267"
+
+lodash.isobject@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.isobject/-/lodash.isobject-2.3.0.tgz#2e16d3fc583da9831968953f2d8e6d73434f6799"
+  dependencies:
+    lodash._objecttypes "~2.3.0"
+
 lodash.keys@^3.0.0:
   version "3.1.2"
   resolved "https://registry.yarnpkg.com/lodash.keys/-/lodash.keys-3.1.2.tgz#4dbc0472b156be50a0b286855d1bd0b0c656098a"
@@ -1072,6 +1220,49 @@ lodash.keys@^3.0.0:
     lodash.isarguments "^3.0.0"
     lodash.isarray "^3.0.0"
 
+lodash.keys@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.keys/-/lodash.keys-2.3.0.tgz#b350f4f92caa9f45a4a2ecf018454cf2f28ae253"
+  dependencies:
+    lodash._renative "~2.3.0"
+    lodash._shimkeys "~2.3.0"
+    lodash.isobject "~2.3.0"
+
+lodash.noop@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.noop/-/lodash.noop-2.3.0.tgz#3059d628d51bbf937cd2a0b6fc3a7f212a669c2c"
+
+lodash.support@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.support/-/lodash.support-2.3.0.tgz#7eaf038af4f0d6aab776b44aa6dcfc80334c9bfd"
+  dependencies:
+    lodash._renative "~2.3.0"
+
+lodash.template@~2.3.x:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.template/-/lodash.template-2.3.0.tgz#4e3e29c433b4cfea675ec835e6f12391c61fd22b"
+  dependencies:
+    lodash._escapestringchar "~2.3.0"
+    lodash._reinterpolate "~2.3.0"
+    lodash.defaults "~2.3.0"
+    lodash.escape "~2.3.0"
+    lodash.keys "~2.3.0"
+    lodash.templatesettings "~2.3.0"
+    lodash.values "~2.3.0"
+
+lodash.templatesettings@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.templatesettings/-/lodash.templatesettings-2.3.0.tgz#303d132c342710040d5a18efaa2d572fd03f8cdc"
+  dependencies:
+    lodash._reinterpolate "~2.3.0"
+    lodash.escape "~2.3.0"
+
+lodash.values@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/lodash.values/-/lodash.values-2.3.0.tgz#ca96fbe60a20b0b0ec2ba2ba5fc6a765bd14a3ba"
+  dependencies:
+    lodash.keys "~2.3.0"
+
 lodash@^4.0.0, lodash@^4.3.0:
   version "4.17.4"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.4.tgz#78203a4d1c328ae1d86dca6460e369b57f4055ae"
@@ -1491,6 +1682,12 @@ source-map@^0.4.4:
   dependencies:
     amdefine ">=0.0.4"
 
+source-map@~0.1.x:
+  version "0.1.43"
+  resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.1.43.tgz#c24bc146ca517c1471f5dacbe2571b2b7f9e3346"
+  dependencies:
+    amdefine ">=0.0.4"
+
 source-map@~0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.2.0.tgz#dab73fbcfc2ba819b4de03bd6f6eaa48164b3f9d"
@@ -1505,6 +1702,15 @@ source-map@~0.6.1:
   version "0.6.1"
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.6.1.tgz#74722af32e9614e9c287a8d0bbde48b5e2f1a263"
 
+sourcemap-validator@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/sourcemap-validator/-/sourcemap-validator-1.1.0.tgz#00454547d1682186e1498a7208e022e8dfa8738f"
+  dependencies:
+    jsesc "~0.3.x"
+    lodash.foreach "~2.3.x"
+    lodash.template "~2.3.x"
+    source-map "~0.1.x"
+
 split@~0.2.10:
   version "0.2.10"
   resolved "https://registry.yarnpkg.com/split/-/split-0.2.10.tgz#67097c601d697ce1368f418f06cd201cf0521a57"