pretty-format: Support HTMLCollection and NodeList in DOMCollection plugin

CHANGELOG.md

@@ -8,6 +8,7 @@
 - `[jest-worker]` [**BREAKING**] Add functionality to call a `setup` method in the worker before the first call and a `teardown` method when ending the farm ([#7014](https://github.com/facebook/jest/pull/7014)).
 - `[jest-config]` [**BREAKING**] Set default `notifyMode` to `failure-change` ([#7024](https://github.com/facebook/jest/pull/7024))
 - `[jest-snapshot]` Enable configurable snapshot paths ([#6143](https://github.com/facebook/jest/pull/6143))
+- `[pretty-format]` Support HTMLCollection and NodeList in DOMCollection plugin ([#7125](https://github.com/facebook/jest/pull/7125))
 
 ### Fixes
 

packages/pretty-format/src/__tests__/dom_collection.test.js

@@ -12,26 +12,111 @@
 'use strict';
 
 const prettyFormat = require('../');
-const {DOMCollection} = prettyFormat.plugins;
+const {DOMCollection, DOMElement} = prettyFormat.plugins;
 const toPrettyPrintTo = require('./expect_util').getPrettyPrint([
   DOMCollection,
+  DOMElement,
 ]);
 
 const expect: any = global.expect;
 expect.extend({toPrettyPrintTo});
 
-describe('DOMCollection Plugin', () => {
-  it('supports a DOMStringMap', () => {
+describe('DOMCollection plugin for object properties', () => {
+  it('supports DOMStringMap', () => {
     const el = document.createElement('div');
     el.dataset.foo = 'bar';
 
     expect(el.dataset).toPrettyPrintTo('DOMStringMap {\n  "foo": "bar",\n}');
   });
 
-  it('supports a NamedNodeMap', () => {
+  it('supports NamedNodeMap', () => {
     const el = document.createElement('div');
     el.setAttribute('foo', 'bar');
 
     expect(el.attributes).toPrettyPrintTo('NamedNodeMap {\n  "foo": "bar",\n}');
   });
 });
+
+describe('DOMCollection plugin for list items', () => {
+  const select = document.createElement('select');
+  select.innerHTML = [
+    '<option value="1">one</option>',
+    '<option value="2">two</option>',
+    '<option value="3">three</option>',
+  ].join('');
+
+  const form = document.createElement('form');
+  form.appendChild(select);
+
+  const expectedOption1 = [
+    '  <option',
+    '    value="1"',
+    '  >',
+    '    one',
+    '  </option>,', // comma because item
+  ].join('\n');
+  const expectedOption2 = [
+    '  <option',
+    '    value="2"',
+    '  >',
+    '    two',
+    '  </option>,', // comma because item
+  ].join('\n');
+  const expectedOption3 = [
+    '  <option',
+    '    value="3"',
+    '  >',
+    '    three',
+    '  </option>,', // comma because item
+  ].join('\n');
+
+  const expectedHTMLCollection = [
+    'HTMLCollection [',
+    expectedOption1,
+    expectedOption2,
+    expectedOption3,
+    ']',
+  ].join('\n');
+
+  it('supports HTMLCollection for getElementsByTagName', () => {
+    const options = form.getElementsByTagName('option');
+    expect(options).toPrettyPrintTo(expectedHTMLCollection);
+  });
+
+  it('supports HTMLCollection for children', () => {
+    expect(select.children).toPrettyPrintTo(expectedHTMLCollection);
+  });
+
+  const expectedNodeList = [
+    'NodeList [',
+    expectedOption1,
+    expectedOption2,
+    expectedOption3,
+    ']',
+  ].join('\n');
+
+  it('supports NodeList for querySelectorAll', () => {
+    const options = form.querySelectorAll('option');
+    expect(options).toPrettyPrintTo(expectedNodeList);
+  });
+
+  it('supports NodeList for childNodes', () => {
+    expect(select.childNodes).toPrettyPrintTo(expectedNodeList);
+  });
+
+  const expectedHTMLOptionsCollection = [
+    'HTMLOptionsCollection [',
+    expectedOption1,
+    expectedOption2,
+    expectedOption3,
+    ']',
+  ].join('\n');
+
+  it('supports HTMLOptionsCollection for options', () => {
+    expect(select.options).toPrettyPrintTo(expectedHTMLOptionsCollection);
+  });
+
+  // Omitted a test for form.elements because constructor.name
+  // is HTMLCollection in jsdom version 11
+  // might become HTMLFormControlsCollectio in jsdom 12
+});

packages/pretty-format/src/plugins/dom_collection.js

@@ -9,29 +9,26 @@
 
 import type {Config, NewPlugin, Printer, Refs} from 'types/PrettyFormat';
 
-import {printObjectProperties} from '../collections';
+import {printListItems, printObjectProperties} from '../collections';
 
 const SPACE = ' ';
 
-const COLLECTION_NAMES = ['DOMStringMap', 'NamedNodeMap'];
+const OBJECT_NAMES = ['DOMStringMap', 'NamedNodeMap'];
+const ARRAY_REGEXP = /^(HTML\w*Collection|NodeList)$/;
+
+const testName = (name: any) =>
+  OBJECT_NAMES.indexOf(name) !== -1 || ARRAY_REGEXP.test(name);
 
 export const test = (val: any) =>
   val &&
   val.constructor &&
-  COLLECTION_NAMES.indexOf(val.constructor.name) !== -1;
-
-const convertCollectionToObject = (collection: any) => {
-  let result = {};
-
-  if (collection.constructor.name === 'NamedNodeMap') {
-    for (let i = 0; i < collection.length; i++) {
-      result[collection[i].name] = collection[i].value;
-    }
-  } else {
-    result = Object.assign({}, collection);
-  }
+  val.constructor.name &&
+  testName(val.constructor.name);
 
-  return result;
+// Convert array of attribute objects to props object.
+const propsReducer = (props, attribute) => {
+  props[attribute.name] = attribute.value;
+  return props;
 };
 
 export const serialize = (
@@ -42,23 +39,36 @@ export const serialize = (
   refs: Refs,
   printer: Printer,
 ): string => {
+  const name = collection.constructor.name;
   if (++depth > config.maxDepth) {
-    return '[' + collection.constructor.name + ']';
+    return '[' + name + ']';
   }
 
   return (
-    collection.constructor.name +
-    SPACE +
-    '{' +
-    printObjectProperties(
-      convertCollectionToObject(collection),
-      config,
-      indentation,
-      depth,
-      refs,
-      printer,
-    ) +
-    '}'
+    (config.min ? '' : name + SPACE) +
+    (OBJECT_NAMES.indexOf(name) !== -1
+      ? '{' +
+        printObjectProperties(
+          name === 'NamedNodeMap'
+            ? Array.prototype.reduce.call(collection, propsReducer, {})
+            : Object.assign({}, collection),
+          config,
+          indentation,
+          depth,
+          refs,
+          printer,
+        ) +
+        '}'
+      : '[' +
+        printListItems(
+          Array.prototype.slice.call(collection),
+          config,
+          indentation,
+          depth,
+          refs,
+          printer,
+        ) +
+        ']')
   );
 };