diff --git a/src/AstAnalyser.js b/src/AstAnalyser.js
index 3ef4a03..d957699 100644
--- a/src/AstAnalyser.js
+++ b/src/AstAnalyser.js
@@ -9,13 +9,14 @@ import isMinified from "is-minified-code";
 // Import Internal Dependencies
 import { SourceFile } from "./SourceFile.js";
 import { isOneLineExpressionExport } from "./utils/index.js";
+import { JsSourceParser } from "./JsSourceParser.js";
 
 export class AstAnalyser {
   /**
    * @constructor
-   * @param { SourceParser } parser
+   * @param { SourceParser } [parser]
    */
-  constructor(parser) {
+  constructor(parser = new JsSourceParser()) {
     this.parser = parser;
   }
 
@@ -35,7 +36,7 @@ export class AstAnalyser {
     // we walk each AST Nodes, this is a purely synchronous I/O
     walk(body, {
       enter(node) {
-      // Skip the root of the AST.
+        // Skip the root of the AST.
         if (Array.isArray(node)) {
           return;
         }
diff --git a/test/AstAnalyser.spec.js b/test/AstAnalyser.spec.js
index fc58856..3b792c3 100644
--- a/test/AstAnalyser.spec.js
+++ b/test/AstAnalyser.spec.js
@@ -225,6 +225,18 @@ describe("AstAnalyser", (t) => {
       assert.strictEqual(preparedSource, "\nconst yo = 'foo'\n");
     });
   });
+
+  describe("constructor", () => {
+    it("should not throw an error when instantiated without a custom parser", () => {
+      assert.doesNotThrow(() => {
+        const analyser = new AstAnalyser();
+        // perform basic operations
+        const result = analyser.analyse("const foo = 'bar';");
+        // compare array of keys to an empty array to ensure there are no dependencies in result
+        assert.deepEqual([...result.dependencies.keys()], []);
+      });
+    });
+  });
 });
 
 let analyser = null;
diff --git a/types/api.d.ts b/types/api.d.ts
index 5d05248..f81ea66 100644
--- a/types/api.d.ts
+++ b/types/api.d.ts
@@ -78,7 +78,7 @@ interface SourceParser {
 }
 
 declare class AstAnalyser {
-  constructor(parser: SourceParser);
+  constructor(parser?: SourceParser);
   analyse: (str: string, options?: Omit<RuntimeOptions, "customParser">) => Report;
   analyzeFile(pathToFile: string, options?: Omit<RuntimeFileOptions, "customParser">): Promise<ReportOnFile>;
 }