diff --git a/src/index.js b/src/index.ts
similarity index 95%
rename from src/index.js
rename to src/index.ts
index ca209c5..8282def 100644
--- a/src/index.js
+++ b/src/index.ts
@@ -158,7 +158,7 @@ function buildParam(key: string, value: any, traditional?: boolean): Array<strin
 * @param traditional Boolean Use the old URI template standard (RFC6570)
 * @returns The generated query string, excluding leading '?'.
 */
-export function buildQueryString(params: Object, traditional?: Boolean): string {
+export function buildQueryString(params?: Object, traditional?: boolean): string {
   let pairs = [];
   let keys = Object.keys(params || {}).sort();
   for (let i = 0, len = keys.length; i < len; i++) {
@@ -203,16 +203,19 @@ function processScalarParam(existedParam: Object, value: Object): Object {
 * @param keys Collection of keys related to this parameter.
 * @param value Parameter value to append.
 */
-function parseComplexParam(queryParams: Object, keys: Object, value: any): void {
+function parseComplexParam(queryParams: Object, keys: (string | number)[], value: any): void {
   let currentParams = queryParams;
   let keysLastIndex = keys.length - 1;
   for (let j = 0; j <= keysLastIndex; j++) {
-    let key = keys[j] === '' ? currentParams.length : keys[j];
+    let key = keys[j] === '' ? (currentParams as any).length : keys[j];
+    if (key === '__proto__') {
+      throw new Error('Prototype pollution detected.');
+    }
     if (j < keysLastIndex) {
       // The value has to be an array or a false value
       // It can happen that the value is no array if the key was repeated with traditional style like `list=1&list[]=2`
       let prevValue = !currentParams[key] || typeof currentParams[key] === 'object' ? currentParams[key] : [currentParams[key]];
-      currentParams = currentParams[key] = prevValue || (isNaN(keys[j + 1]) ? {} : []);
+      currentParams = currentParams[key] = prevValue || (isNaN(keys[j + 1] as number) ? {} : []);
     } else {
       currentParams = currentParams[key] = value;
     }
diff --git a/test/path.spec.js b/test/path.spec.js
deleted file mode 100644
index d8066a3..0000000
--- a/test/path.spec.js
+++ /dev/null
@@ -1,311 +0,0 @@
-import { relativeToFile, join, parseQueryString, buildQueryString } from '../src/index';
-
-describe('relativeToFile', () => {
-  it('can make a dot path relative to a simple file', () => {
-    var file = 'some/file.html';
-    var path = './other/module';
-
-    expect(relativeToFile(path, file)).toBe('some/other/module');
-  });
-
-  it('can make a dot path relative to an absolute file', () => {
-    var file = 'http://durandal.io/some/file.html';
-    var path = './other/module';
-
-    expect(relativeToFile(path, file)).toBe('http://durandal.io/some/other/module');
-  });
-
-  it('can make a double dot path relative to an absolute file', () => {
-    var file = 'http://durandal.io/some/file.html';
-    var path = '../other/module';
-
-    expect(relativeToFile(path, file)).toBe('http://durandal.io/other/module');
-  });
-
-  it('returns path if null file provided', () => {
-    var file = null;
-    var path = 'module';
-
-    expect(relativeToFile(path, file)).toBe('module');
-  });
-
-  it('returns path if empty file provided', () => {
-    var file = '';
-    var path = 'module';
-
-    expect(relativeToFile(path, file)).toBe('module');
-  });
-});
-
-describe('join', () => {
-  it('can combine two simple paths', () => {
-    var path1 = 'one';
-    var path2 = 'two';
-
-    expect(join(path1, path2)).toBe('one/two');
-  });
-
-  it('can combine an absolute path and a simple path', () => {
-    var path1 = '/one';
-    var path2 = 'two';
-
-    expect(join(path1, path2)).toBe('/one/two');
-  });
-
-  it('can combine an absolute path and a simple path with slash', () => {
-    var path1 = '/one';
-    var path2 = '/two';
-
-    expect(join(path1, path2)).toBe('/one/two');
-  });
-
-  it('can combine a single slash and a simple path', () => {
-    var path1 = '/';
-    var path2 = 'two';
-
-    expect(join(path1, path2)).toBe('/two');
-  });
-
-  it('can combine a single slash and a simple path with slash', () => {
-    var path1 = '/';
-    var path2 = '/two';
-
-    expect(join(path1, path2)).toBe('/two');
-  });
-
-  it('can combine an absolute path with protocol and a simple path', () => {
-    var path1 = 'http://durandal.io';
-    var path2 = 'two';
-
-    expect(join(path1, path2)).toBe('http://durandal.io/two');
-  });
-
-  it('can combine an absolute path with protocol and a simple path with slash', () => {
-    var path1 = 'http://durandal.io';
-    var path2 = '/two';
-
-    expect(join(path1, path2)).toBe('http://durandal.io/two');
-  });
-
-  it('can combine an absolute path and a simple path with a dot', () => {
-    var path1 = 'http://durandal.io';
-    var path2 = './two';
-
-    expect(join(path1, path2)).toBe('http://durandal.io/two');
-  });
-
-  it('can combine a simple path and a relative path', () => {
-    var path1 = 'one';
-    var path2 = '../two';
-
-    expect(join(path1, path2)).toBe('two');
-  });
-
-  it('can combine an absolute path and a relative path', () => {
-    var path1 = 'http://durandal.io/somewhere';
-    var path2 = '../two';
-
-    expect(join(path1, path2)).toBe('http://durandal.io/two');
-  });
-
-  it('can combine a protocol independent path and a simple path', () => {
-    var path1 = '//durandal.io';
-    var path2 = 'two';
-
-    expect(join(path1, path2)).toBe('//durandal.io/two');
-  });
-
-  it('can combine a protocol independent path and a simple path with slash', () => {
-    var path1 = '//durandal.io';
-    var path2 = '/two';
-
-    expect(join(path1, path2)).toBe('//durandal.io/two');
-  });
-
-  it('can combine a protocol independent path and a simple path with a dot', () => {
-    var path1 = '//durandal.io';
-    var path2 = './two';
-
-    expect(join(path1, path2)).toBe('//durandal.io/two');
-  });
-
-  it('can combine a protocol independent path and a relative path', () => {
-    var path1 = '//durandal.io/somewhere';
-    var path2 = '../two';
-
-    expect(join(path1, path2)).toBe('//durandal.io/two');
-  });
-
-  it('can combine a complex path and a relative path', () => {
-    var path1 = 'one/three';
-    var path2 = '../two';
-
-    expect(join(path1, path2)).toBe('one/two');
-  });
-
-  it('returns path2 if path1 null', () => {
-    var path1 = null;
-    var path2 = 'two';
-
-    expect(join(path1, path2)).toBe('two');
-  });
-
-  it('returns path2 if path1 empty', () => {
-    var path1 = '';
-    var path2 = 'two';
-
-    expect(join(path1, path2)).toBe('two');
-  });
-
-  it('returns path1 if path2 null', () => {
-    var path1 = 'one';
-    var path2 = null;
-
-    expect(join(path1, path2)).toBe('one');
-  });
-
-  it('returns path1 if path2 empty', () => {
-    var path1 = 'one';
-    var path2 = '';
-
-    expect(join(path1, path2)).toBe('one');
-  });
-
-  it('should retain leading .. in path1', () => {
-    var path1 = '../one';
-    var path2 = './two';
-
-    expect(join(path1, path2)).toBe('../one/two');
-  });
-
-  it('should retain consecutive leading .. in path1', () => {
-    var path1 = '../../one';
-    var path2 = './two';
-
-    expect(join(path1, path2)).toBe('../../one/two');
-  });
-
-  it('should handle .. in path1 and path2', () => {
-    var path1 = '../../one';
-    var path2 = '../two';
-
-    expect(join(path1, path2)).toBe('../../two');
-  });
-
-  it('should merge .. in path1 and path2', () => {
-    var path1 = '../../one';
-    var path2 = '../../two';
-
-    expect(join(path1, path2)).toBe('../../../two');
-  });
-
-  it('should retain consecutive leading .. but not other .. in path1', () => {
-    var path1 = '../../one/../three';
-    var path2 = './two';
-
-    expect(join(path1, path2)).toBe('../../three/two');
-  });
-
-  it('should respect a trailing slash', () => {
-    var path1 = 'one/';
-    var path2 = 'two/';
-
-    expect(join(path1, path2)).toBe('one/two/');
-  });
-
-  it('should respect file:/// protocol with three slashes (empty host)', () => {
-    var path1 = 'file:///one';
-    var path2 = '/two';
-
-    expect(join(path1, path2)).toBe('file:///one/two');
-  });
-
-  it('should respect file:// protocol with two slashes (host given)', () => {
-    var path1 = 'file://localhost:8080';
-    var path2 = '/two';
-
-    expect(join(path1, path2)).toBe('file://localhost:8080/two');
-  });
-
-  it('should allow scheme-relative URL that uses colons in the path', () => {
-    var path1 = '//localhost/one:/';
-    var path2 = '/two';
-
-    expect(join(path1, path2)).toBe('//localhost/one:/two');
-  });
-
-  it('should not add more than two leading slashes to http:// protocol', () => {
-    var path1 = 'http:///';
-    var path2 = '/two';
-
-    expect(join(path1, path2)).toBe('http://two');
-  });
-});
-
-describe('query strings', () => {
-  it('should build query strings', () => {
-    let gen = buildQueryString;
-
-    expect(gen()).toBe('');
-    expect(gen(null)).toBe('');
-    expect(gen({})).toBe('');
-    expect(gen({ a: null })).toBe('');
-
-    expect(gen({ '': 'a' })).toBe('=a');
-    expect(gen({ a: 'b' })).toBe('a=b');
-    expect(gen({ a: 'b', c: 'd' })).toBe('a=b&c=d');
-    expect(gen({ a: 'b', c: 'd' }, true)).toBe('a=b&c=d');
-    expect(gen({ a: 'b', c: null })).toBe('a=b');
-    expect(gen({ a: 'b', c: null }, true)).toBe('a=b');
-
-    expect(gen({ a: ['b', 'c'] })).toBe('a%5B%5D=b&a%5B%5D=c');
-    expect(gen({ a: ['b', 'c'] }, true)).toBe('a=b&a=c');
-    expect(gen({ '&': ['b', 'c'] })).toBe('%26%5B%5D=b&%26%5B%5D=c');
-    expect(gen({ '&': ['b', 'c'] }, true)).toBe('%26=b&%26=c');
-
-    expect(gen({ a: '&' })).toBe('a=%26');
-    expect(gen({ '&': 'a' })).toBe('%26=a');
-    expect(gen({ a: true })).toBe('a=true');
-    expect(gen({ '$test': true })).toBe('$test=true');
-
-    expect(gen({ obj: { a: 5, b: "str", c: false } })).toBe('obj%5Ba%5D=5&obj%5Bb%5D=str&obj%5Bc%5D=false');
-    expect(gen({ obj: { a: 5, b: "str", c: false } }, true)).toBe('obj=%5Bobject%20Object%5D');
-    expect(gen({ obj:{ a: 5, b: undefined}})).toBe('obj%5Ba%5D=5');
-
-    expect(gen({a: {b: ['c','d', ['f', 'g']]}})).toBe('a%5Bb%5D%5B%5D=c&a%5Bb%5D%5B%5D=d&a%5Bb%5D%5B2%5D%5B%5D=f&a%5Bb%5D%5B2%5D%5B%5D=g');
-    expect(gen({a: {b: ['c','d', ['f', 'g']]}}, true)).toBe('a=%5Bobject%20Object%5D');
-    expect(gen({a: ['c','d', ['f', 'g']]}, true)).toBe('a=c&a=d&a=f%2Cg');
-    expect(gen({a: ['c','d', {f: 'g'}]}, true)).toBe('a=c&a=d&a=%5Bobject%20Object%5D');
-  });
-
-  it('should parse query strings', () => {
-    let parse = parseQueryString;
-
-    expect(parse('')).toEqual({});
-    expect(parse('=')).toEqual({});
-    expect(parse('&')).toEqual({});
-    expect(parse('?')).toEqual({});
-
-    expect(parse('a')).toEqual({ a: true });
-    expect(parse('a&b')).toEqual({ a: true, b: true });
-    expect(parse('a=')).toEqual({ a: '' });
-    expect(parse('a=&b=')).toEqual({ a: '', b: '' });
-
-    expect(parse('a=b')).toEqual({ a: 'b' });
-    expect(parse('a=b&c=d')).toEqual({ a: 'b', c: 'd' });
-    expect(parse('a=b&&c=d')).toEqual({ a: 'b', c: 'd' });
-    expect(parse('a=b&a=c')).toEqual({ a: ['b', 'c'] });
-
-    expect(parse('a=b&c=d=')).toEqual({ a: 'b', c: 'd' });
-    expect(parse('a=b&c=d==')).toEqual({ a: 'b', c: 'd' });
-
-    expect(parse('a=%26')).toEqual({ a: '&' });
-    expect(parse('%26=a')).toEqual({ '&': 'a' });
-    expect(parse('%26[]=b&%26[]=c')).toEqual({ '&': ['b', 'c'] });
-
-    expect(parse('a[b]=c&a[d]=e')).toEqual({a: {b: 'c', d: 'e'}});
-    expect(parse('a[b][c][d]=e')).toEqual({a: {b: {c: {d: 'e'}}}});
-    expect(parse('a[b][]=c&a[b][]=d&a[b][2][]=f&a[b][2][]=g')).toEqual({a: {b: ['c','d', ['f', 'g']]}});
-    expect(parse('a[0]=b')).toEqual({a: ['b']});
-  });
-});
diff --git a/test/path.spec.ts b/test/path.spec.ts
new file mode 100644
index 0000000..f4ce35d
--- /dev/null
+++ b/test/path.spec.ts
@@ -0,0 +1,344 @@
+import { relativeToFile, join, parseQueryString, buildQueryString } from '../src/index';
+import assert from 'assert';
+
+const expect = (input: any) => {
+  return {
+    toBe: (output: any) => {
+      assert.strictEqual(input, output);
+    },
+    toEqual: (output: any) => {
+      assert.deepStrictEqual(input, output)
+    }
+  }
+}
+
+describe('relativeToFile', () => {
+  it('can make a dot path relative to a simple file', () => {
+    const file = 'some/file.html';
+    const path = './other/module';
+
+    expect(relativeToFile(path, file)).toBe('some/other/module');
+  });
+
+  it('can make a dot path relative to an absolute file', () => {
+    const file = 'http://durandal.io/some/file.html';
+    const path = './other/module';
+
+    expect(relativeToFile(path, file)).toBe('http://durandal.io/some/other/module');
+  });
+
+  it('can make a double dot path relative to an absolute file', () => {
+    const file = 'http://durandal.io/some/file.html';
+    const path = '../other/module';
+
+    expect(relativeToFile(path, file)).toBe('http://durandal.io/other/module');
+  });
+
+  it('returns path if null file provided', () => {
+    const file = null;
+    const path = 'module';
+
+    expect(relativeToFile(path, file)).toBe('module');
+  });
+
+  it('returns path if empty file provided', () => {
+    const file = '';
+    const path = 'module';
+
+    expect(relativeToFile(path, file)).toBe('module');
+  });
+});
+
+describe('join', () => {
+  it('can combine two simple paths', () => {
+    const path1 = 'one';
+    const path2 = 'two';
+
+    expect(join(path1, path2)).toBe('one/two');
+  });
+
+  it('can combine an absolute path and a simple path', () => {
+    const path1 = '/one';
+    const path2 = 'two';
+
+    expect(join(path1, path2)).toBe('/one/two');
+  });
+
+  it('can combine an absolute path and a simple path with slash', () => {
+    const path1 = '/one';
+    const path2 = '/two';
+
+    expect(join(path1, path2)).toBe('/one/two');
+  });
+
+  it('can combine a single slash and a simple path', () => {
+    const path1 = '/';
+    const path2 = 'two';
+
+    expect(join(path1, path2)).toBe('/two');
+  });
+
+  it('can combine a single slash and a simple path with slash', () => {
+    const path1 = '/';
+    const path2 = '/two';
+
+    expect(join(path1, path2)).toBe('/two');
+  });
+
+  it('can combine an absolute path with protocol and a simple path', () => {
+    const path1 = 'http://durandal.io';
+    const path2 = 'two';
+
+    expect(join(path1, path2)).toBe('http://durandal.io/two');
+  });
+
+  it('can combine an absolute path with protocol and a simple path with slash', () => {
+    const path1 = 'http://durandal.io';
+    const path2 = '/two';
+
+    expect(join(path1, path2)).toBe('http://durandal.io/two');
+  });
+
+  it('can combine an absolute path and a simple path with a dot', () => {
+    const path1 = 'http://durandal.io';
+    const path2 = './two';
+
+    expect(join(path1, path2)).toBe('http://durandal.io/two');
+  });
+
+  it('can combine a simple path and a relative path', () => {
+    const path1 = 'one';
+    const path2 = '../two';
+
+    expect(join(path1, path2)).toBe('two');
+  });
+
+  it('can combine an absolute path and a relative path', () => {
+    const path1 = 'http://durandal.io/somewhere';
+    const path2 = '../two';
+
+    expect(join(path1, path2)).toBe('http://durandal.io/two');
+  });
+
+  it('can combine a protocol independent path and a simple path', () => {
+    const path1 = '//durandal.io';
+    const path2 = 'two';
+
+    expect(join(path1, path2)).toBe('//durandal.io/two');
+  });
+
+  it('can combine a protocol independent path and a simple path with slash', () => {
+    const path1 = '//durandal.io';
+    const path2 = '/two';
+
+    expect(join(path1, path2)).toBe('//durandal.io/two');
+  });
+
+  it('can combine a protocol independent path and a simple path with a dot', () => {
+    const path1 = '//durandal.io';
+    const path2 = './two';
+
+    expect(join(path1, path2)).toBe('//durandal.io/two');
+  });
+
+  it('can combine a protocol independent path and a relative path', () => {
+    const path1 = '//durandal.io/somewhere';
+    const path2 = '../two';
+
+    expect(join(path1, path2)).toBe('//durandal.io/two');
+  });
+
+  it('can combine a complex path and a relative path', () => {
+    const path1 = 'one/three';
+    const path2 = '../two';
+
+    expect(join(path1, path2)).toBe('one/two');
+  });
+
+  it('returns path2 if path1 null', () => {
+    const path1 = null;
+    const path2 = 'two';
+
+    expect(join(path1, path2)).toBe('two');
+  });
+
+  it('returns path2 if path1 empty', () => {
+    const path1 = '';
+    const path2 = 'two';
+
+    expect(join(path1, path2)).toBe('two');
+  });
+
+  it('returns path1 if path2 null', () => {
+    const path1 = 'one';
+    const path2 = null;
+
+    expect(join(path1, path2)).toBe('one');
+  });
+
+  it('returns path1 if path2 empty', () => {
+    const path1 = 'one';
+    const path2 = '';
+
+    expect(join(path1, path2)).toBe('one');
+  });
+
+  it('should retain leading .. in path1', () => {
+    const path1 = '../one';
+    const path2 = './two';
+
+    expect(join(path1, path2)).toBe('../one/two');
+  });
+
+  it('should retain consecutive leading .. in path1', () => {
+    const path1 = '../../one';
+    const path2 = './two';
+
+    expect(join(path1, path2)).toBe('../../one/two');
+  });
+
+  it('should handle .. in path1 and path2', () => {
+    const path1 = '../../one';
+    const path2 = '../two';
+
+    expect(join(path1, path2)).toBe('../../two');
+  });
+
+  it('should merge .. in path1 and path2', () => {
+    const path1 = '../../one';
+    const path2 = '../../two';
+
+    expect(join(path1, path2)).toBe('../../../two');
+  });
+
+  it('should retain consecutive leading .. but not other .. in path1', () => {
+    const path1 = '../../one/../three';
+    const path2 = './two';
+
+    expect(join(path1, path2)).toBe('../../three/two');
+  });
+
+  it('should respect a trailing slash', () => {
+    const path1 = 'one/';
+    const path2 = 'two/';
+
+    expect(join(path1, path2)).toBe('one/two/');
+  });
+
+  it('should respect file:/// protocol with three slashes (empty host)', () => {
+    const path1 = 'file:///one';
+    const path2 = '/two';
+
+    expect(join(path1, path2)).toBe('file:///one/two');
+  });
+
+  it('should respect file:// protocol with two slashes (host given)', () => {
+    const path1 = 'file://localhost:8080';
+    const path2 = '/two';
+
+    expect(join(path1, path2)).toBe('file://localhost:8080/two');
+  });
+
+  it('should allow scheme-relative URL that uses colons in the path', () => {
+    const path1 = '//localhost/one:/';
+    const path2 = '/two';
+
+    expect(join(path1, path2)).toBe('//localhost/one:/two');
+  });
+
+  it('should not add more than two leading slashes to http:// protocol', () => {
+    const path1 = 'http:///';
+    const path2 = '/two';
+
+    expect(join(path1, path2)).toBe('http://two');
+  });
+});
+
+describe('query strings', () => {
+  interface IBuildTestCase {
+    input: any;
+    traditional?: boolean;
+    output: string;
+  }
+  const testCases: IBuildTestCase[] = [
+    { input: undefined, output: '' },
+    { input: null, output: '' },
+    { input: {}, output: '' },
+    { input: { a: null }, output: '' },
+    { input: { '': 'a' }, output: '=a' },
+    { input: { a: 'b' }, output: 'a=b' },
+    { input: { a: 'b', c: 'd' }, output: 'a=b&c=d' },
+    { input: { a: 'b', c: 'd' }, traditional: true, output: 'a=b&c=d' },
+    { input: { a: 'b', c: null }, output: 'a=b' },
+    { input: { a: 'b', c: null }, traditional: true, output: 'a=b' },
+    { input: { a: ['b', 'c'] }, output: 'a%5B%5D=b&a%5B%5D=c' },
+    { input: { a: ['b', 'c'] }, traditional: true, output: 'a=b&a=c' },
+    { input: { '&': ['b', 'c'] }, output: '%26%5B%5D=b&%26%5B%5D=c' },
+    { input: { '&': ['b', 'c'] }, traditional: true, output: '%26=b&%26=c' },
+
+    { input: { a: '&' }, output: 'a=%26' },
+    { input: { '&': 'a' }, output: '%26=a' },
+    { input: { a: true }, output: 'a=true' },
+    { input: { '$test': true }, output: '$test=true' },
+
+    { input: { obj: { a: 5, b: "str", c: false } }, output: 'obj%5Ba%5D=5&obj%5Bb%5D=str&obj%5Bc%5D=false' },
+    { input: { obj: { a: 5, b: "str", c: false } }, traditional: true, output: 'obj=%5Bobject%20Object%5D' },
+    { input: { obj: { a: 5, b: undefined } }, output: 'obj%5Ba%5D=5' },
+
+    { input: { a: { b: ['c', 'd', ['f', 'g']] } }, output: 'a%5Bb%5D%5B%5D=c&a%5Bb%5D%5B%5D=d&a%5Bb%5D%5B2%5D%5B%5D=f&a%5Bb%5D%5B2%5D%5B%5D=g' },
+    { input: { a: { b: ['c', 'd', ['f', 'g']] } }, traditional: true, output: 'a=%5Bobject%20Object%5D' },
+    { input: { a: ['c', 'd', ['f', 'g']] }, traditional: true, output: 'a=c&a=d&a=f%2Cg' },
+    { input: { a: ['c', 'd', { f: 'g' }] }, traditional: true, output: 'a=c&a=d&a=%5Bobject%20Object%5D' },
+  ];
+
+  testCases.forEach(({ input, output, traditional }) => {
+    it(`builds ${input instanceof Object ? JSON.stringify(input) : input} to "${output}"`, () => {
+      expect(buildQueryString(input, traditional)).toBe(output);
+    });
+  });
+
+  interface IParseTestCase {
+    input: string;
+    output: any;
+  }
+
+  const parseTestCases: IParseTestCase[] = [
+    { input: '', output: {} },
+    { input: '=', output: {} },
+    { input: '&', output: {} },
+    { input: '?', output: {} },
+
+    { input: 'a', output: { a: true } },
+    { input: 'a&b', output: { a: true, b: true } },
+    { input: 'a=', output: { a: '' } },
+    { input: 'a=&b=', output: { a: '', b: '' } },
+
+    { input: 'a=b', output: { a: 'b' } },
+    { input: 'a=b&c=d', output: { a: 'b', c: 'd' } },
+    { input: 'a=b&&c=d', output: { a: 'b', c: 'd' } },
+    { input: 'a=b&a=c', output: { a: ['b', 'c'] } },
+
+    { input: 'a=b&c=d=', output: { a: 'b', c: 'd' } },
+    { input: 'a=b&c=d==', output: { a: 'b', c: 'd' } },
+
+    { input: 'a=%26', output: { a: '&' } },
+    { input: '%26=a', output: { '&': 'a' } },
+    { input: '%26[]=b&%26[]=c', output: { '&': ['b', 'c'] } },
+
+    { input: 'a[b]=c&a[d]=e', output: { a: { b: 'c', d: 'e' } } },
+    { input: 'a[b][c][d]=e', output: { a: { b: { c: { d: 'e' } } } } },
+    { input: 'a[b][]=c&a[b][]=d&a[b][2][]=f&a[b][2][]=g', output: { a: { b: ['c', 'd', ['f', 'g']] } } },
+    { input: 'a[0]=b', output: { a: ['b'] } },
+  ];
+
+  parseTestCases.forEach(({ input, output }) => {
+    it(`parses ${input} to "${JSON.stringify(output)}"`, () => {
+      expect(parseQueryString(input)).toEqual(output);
+    });
+  });
+
+  it('does not pollute prototype', () => {
+    const path1 = '__proto__[asdf]=asdf';
+    assert.throws(() => parseQueryString(path1), 'Prototype pollution detected');
+  });
+});