diff --git a/implementations/javascript/packages/core/src/reader.ts b/implementations/javascript/packages/core/src/reader.ts
index 75b5e14..2133a94 100644
--- a/implementations/javascript/packages/core/src/reader.ts
+++ b/implementations/javascript/packages/core/src/reader.ts
@@ -148,6 +148,7 @@ export class ReaderState {
 
     readDigit0(kind: IntOrFloat, acc: string, k: IntContinuation): Numeric {
         while (true) {
+            if (this.atEnd()) break;
             const ch = this.peek();
             if (!(ch >= '0' && ch <= '9')) break;
             this.advance();
@@ -157,7 +158,7 @@ export class ReaderState {
     }
 
     readFracexp(kind: IntOrFloat, acc: string): Numeric {
-        if (this.peek() === '.') {
+        if (!this.atEnd() && this.peek() === '.') {
             this.advance();
             return this.readDigit1('float', acc + '.', (kind, acc) => this.readExp(kind, acc));
         }
@@ -165,7 +166,7 @@ export class ReaderState {
     }
 
     readExp(kind: IntOrFloat, acc: string): Numeric {
-        const ch = this.peek();
+        const ch = this.atEnd() ? '' : this.peek();
         if (ch === 'e' || ch === 'E') {
             this.advance();
             return this.readSignAndExp(acc + ch);
@@ -185,7 +186,7 @@ export class ReaderState {
     finishNumber(kind: IntOrFloat, acc: string): Numeric {
         const i = parseFloat(acc);
         if (kind === 'int') return i;
-        const ch = this.peek();
+        const ch = this.atEnd() ? '' : this.peek();
         if (ch === 'f' || ch === 'F') {
             this.advance();
             return Single(i);
diff --git a/implementations/javascript/packages/core/test/reader.test.ts b/implementations/javascript/packages/core/test/reader.test.ts
index 3484196..3a6e1a3 100644
--- a/implementations/javascript/packages/core/test/reader.test.ts
+++ b/implementations/javascript/packages/core/test/reader.test.ts
@@ -1,4 +1,4 @@
-import { Bytes, Decoder, genericEmbeddedType, encode, Reader } from '../src/index';
+import { Bytes, Decoder, genericEmbeddedType, encode, Reader, Double } from '../src/index';
 import './test-utils';
 
 import * as fs from 'fs';
@@ -28,4 +28,10 @@ describe('reading common test suite', () => {
         }));
         expect(bs).toEqual(new Uint8Array(samples_bin));
     });
+
+    it('should be ok with no whitespace at the end of a numeric input', () => {
+        expect(new Reader('123').next()).toEqual(123);
+        expect(new Reader('123.0').next()).toEqual(Double(123.0));
+        expect(new Reader('123.00').next()).toEqual(Double(123.0));
+    });
 });