[fix] mount/shallow: do not dedupe in flatMap

Fixes #1275

Author: ljharb

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

@@ -2348,6 +2348,24 @@ describeWithDOM('mount', () => {
         expect(wrapper.children().children().at(2).hasClass('baz')).to.equal(true);
       });
     });
+
+    it('returns duplicates untouched', () => {
+      class Foo extends React.Component {
+        render() {
+          const foo = 'Foo';
+          return (
+            <div>
+              {foo} Bar {foo} Bar {foo}
+            </div>
+          )
+        }
+      }
+
+      const wrapper = mount(<Foo />);
+      const children = wrapper.children();
+      const textNodes = children.map(x => x.text());
+      expect(textNodes).to.eql(['Foo Bar Foo Bar Foo']);
+    });
   });
 
   describe('.childAt(index)', () => {

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

@@ -2154,6 +2154,23 @@ describe('shallow', () => {
       });
     });
 
+    it('returns duplicates untouched', () => {
+      class Foo extends React.Component {
+        render() {
+          const foo = 'Foo';
+          return (
+            <div>
+              {foo} Bar {foo} Bar {foo}
+            </div>
+          )
+        }
+      }
+
+      const wrapper = shallow(<Foo />);
+      const children = wrapper.children();
+      const textNodes = children.map(x => x.text());
+      expect(textNodes).to.eql(['Foo', ' Bar ', 'Foo', ' Bar ', 'Foo']);
+    });
   });
 
   describe('.childAt(index)', () => {

packages/enzyme/src/ReactWrapper.js

@@ -1,6 +1,5 @@
 import cheerio from 'cheerio';
 import flatten from 'lodash/flatten';
-import unique from 'lodash/uniq';
 import compact from 'lodash/compact';
 
 import {
@@ -888,8 +887,7 @@ class ReactWrapper {
   flatMap(fn) {
     const nodes = this.getNodesInternal().map((n, i) => fn.call(this, this.wrap(n), i));
     const flattened = flatten(nodes, true);
-    const uniques = unique(flattened);
-    const compacted = compact(uniques);
+    const compacted = compact(flattened);
     return this.wrap(compacted);
   }
 

packages/enzyme/src/ShallowWrapper.js

@@ -1,5 +1,4 @@
 import flatten from 'lodash/flatten';
-import unique from 'lodash/uniq';
 import compact from 'lodash/compact';
 import cheerio from 'cheerio';
 
@@ -1094,8 +1093,7 @@ class ShallowWrapper {
   flatMap(fn) {
     const nodes = this.getNodesInternal().map((n, i) => fn.call(this, this.wrap(n), i));
     const flattened = flatten(nodes, true);
-    const uniques = unique(flattened);
-    const compacted = compact(uniques);
+    const compacted = compact(flattened);
     return this.wrap(compacted);
   }