Fix .exists not accepting any EnzymeSelector

`.exists`, since [#1695](#1695), accepts an optional selector. Unfortunately, this optional parameter was limited to the `string` type whereas the documentation inform us it can be any valid [EnzymeSelector](https://airbnb.io/enzyme/docs/api/selector.html).
This commit fixes this limitation by accepting any type for the parameter and using `.find()` internal functions to throw any necessary `TypeError`.

Author: btimo

SUMMARY.md

@@ -33,7 +33,7 @@
     * [equals(node)](/docs/api/ShallowWrapper/equals.md)
     * [every(selector)](/docs/api/ShallowWrapper/every.md)
     * [everyWhere(predicate)](/docs/api/ShallowWrapper/everyWhere.md)
-    * [exists()](/docs/api/ShallowWrapper/exists.md)
+    * [exists([selector])](/docs/api/ShallowWrapper/exists.md)
     * [filter(selector)](/docs/api/ShallowWrapper/filter.md)
     * [filterWhere(predicate)](/docs/api/ShallowWrapper/filterWhere.md)
     * [find(selector)](/docs/api/ShallowWrapper/find.md)
@@ -91,7 +91,7 @@
     * [detach()](/docs/api/ReactWrapper/detach.md)
     * [every(selector)](/docs/api/ReactWrapper/every.md)
     * [everyWhere(predicate)](/docs/api/ReactWrapper/everyWhere.md)
-    * [exists()](/docs/api/ReactWrapper/exists.md)
+    * [exists([selector])](/docs/api/ReactWrapper/exists.md)
     * [filter(selector)](/docs/api/ReactWrapper/filter.md)
     * [filterWhere(predicate)](/docs/api/ReactWrapper/filterWhere.md)
     * [find(selector)](/docs/api/ReactWrapper/find.md)

packages/enzyme-test-suite/test/ReactWrapper-spec.jsx

@@ -8,7 +8,7 @@ import isEqual from 'lodash.isequal';
 import {
   mount,
   render,
-  ReactWrapper,
+  ReactWrapper, shallow,
 } from 'enzyme';
 import {
   ITERATOR_SYMBOL,
@@ -4753,6 +4753,14 @@ describeWithDOM('mount', () => {
       });
     });
     describe('with argument', () => {
+      it('throws on invalid EnzymeSelector', () => {
+        const wrapper = shallow(<div />);
+
+        expect(() => wrapper.exists(null)).to.throw(TypeError);
+        expect(() => wrapper.exists(undefined)).to.throw(TypeError);
+        expect(() => wrapper.exists(45)).to.throw(TypeError);
+        expect(() => wrapper.exists({})).to.throw(TypeError);
+      });
       it('returns .find(arg).exists() instead', () => {
         const wrapper = mount(<div />);
         const fakeFindExistsReturnVal = Symbol('fake .find(arg).exists() return value');

packages/enzyme-test-suite/test/ShallowWrapper-spec.jsx

@@ -4553,6 +4553,15 @@ describe('shallow', () => {
       });
     });
     describe('with argument', () => {
+      it('throws on invalid EnzymeSelector', () => {
+        const wrapper = shallow(<div />);
+
+        expect(() => wrapper.exists(null)).to.throw(TypeError);
+        expect(() => wrapper.exists(undefined)).to.throw(TypeError);
+        expect(() => wrapper.exists(45)).to.throw(TypeError);
+        expect(() => wrapper.exists({})).to.throw(TypeError);
+      });
+
       it('returns .find(arg).exists() instead', () => {
         const wrapper = shallow(<div />);
         const fakeFindExistsReturnVal = Symbol('fake .find(arg).exists() return value');

packages/enzyme/src/ReactWrapper.js

@@ -1077,10 +1077,7 @@ class ReactWrapper {
    * @returns {boolean}
    */
   exists(selector = null) {
-    if (arguments.length > 0 && typeof selector !== 'string') {
-      throw new TypeError('`selector` argument must be a string, if present.');
-    }
-    return typeof selector === 'string' ? this.find(selector).exists() : this.length > 0;
+    return arguments.length > 0 ? this.find(selector).exists() : this.length > 0;
   }
 
   /**

packages/enzyme/src/ShallowWrapper.js

@@ -740,7 +740,7 @@ class ShallowWrapper {
   /**
    * Finds every node in the render tree of the current wrapper that matches the provided selector.
    *
-   * @param {String|Function} selector
+   * @param {String|Function|Object} selector
    * @returns {ShallowWrapper}
    */
   find(selector) {
@@ -1329,14 +1329,11 @@ class ShallowWrapper {
    * Returns true if the current wrapper has nodes. False otherwise.
    * If called with a selector it returns `.find(selector).exists()` instead.
    *
-   * @param {String|Function} selector (optional)
+   * @param {String|Function|Object} selector (optional)
    * @returns {boolean}
    */
   exists(selector = null) {
-    if (arguments.length > 0 && typeof selector !== 'string') {
-      throw new TypeError('`selector` argument must be a string, if present.');
-    }
-    return typeof selector === 'string' ? this.find(selector).exists() : this.length > 0;
+    return arguments.length > 0 ? this.find(selector).exists() : this.length > 0;
   }
 
   /**