converted migrations_table class component to functional component (#27956)

* converted migrations_table  class component to functional component

* added  dependencylist for useffect & use memo for caching

* Added tests

* Remove commented code and used renderWithContext instead  of render(withIntl(..))

---------

Co-authored-by: Ezekiel <ezekiel@itsmart.my>
Co-authored-by: Mattermost Build <build@mattermost.com>

webapp/channels/src/components/admin_console/__snapshots__/database_settings.test.tsx.snap

@@ -381,7 +381,7 @@ exports[`components/DatabaseSettings should match snapshot 1`] = `
           <div
             className="migrations-table-setting"
           >
-            <Connect(MigrationsTable)
+            <Connect(Component)
               createHelpText={
                 <Memo(MemoizedFormattedMessage)
                   defaultMessage="All applied migrations."

webapp/channels/src/components/admin_console/database/__snapshots__/migrations_table.test.tsx.snap

@@ -0,0 +1,42 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`components/MigrationsTable should match snapshot when there are no migrations 1`] = `
+<div
+  className="MigrationsTable migrations-table__panel"
+>
+  <div
+    className="help-text"
+  >
+    <MemoizedFormattedMessage
+      defaultMessage="All applied migrations."
+      id="admin.database.migrations_table.help_text"
+    />
+  </div>
+  <div
+    className="migrations-table__table"
+  >
+    <table
+      className="table"
+      data-testid="migrationsTable"
+    >
+      <thead>
+        <tr>
+          <th>
+            <MemoizedFormattedMessage
+              defaultMessage="Version"
+              id="admin.database.migrations_table.version"
+            />
+          </th>
+          <th>
+            <MemoizedFormattedMessage
+              defaultMessage="Name"
+              id="admin.database.migrations_table.name"
+            />
+          </th>
+        </tr>
+      </thead>
+      <tbody />
+    </table>
+  </div>
+</div>
+`;

webapp/channels/src/components/admin_console/database/migrations_table.test.tsx

@@ -0,0 +1,79 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+import {act, screen, waitFor} from '@testing-library/react';
+import {shallow} from 'enzyme';
+import React from 'react';
+import {FormattedMessage} from 'react-intl';
+
+import type {SchemaMigration} from '@mattermost/types/admin';
+
+import type {ActionResult} from 'mattermost-redux/types/actions';
+
+import {renderWithContext} from 'tests/react_testing_utils';
+
+import MigrationsTable from './migrations_table';
+
+const migrationsMockData: SchemaMigration[] = [];
+
+describe('components/MigrationsTable', () => {
+    const createHelpText = (
+        <FormattedMessage
+            id='admin.database.migrations_table.help_text'
+            defaultMessage='All applied migrations.'
+        />
+    );
+
+    const baseProps = {
+        createHelpText,
+        className: '',
+        actions: {
+            getAppliedSchemaMigrations: (jest.fn()).mockResolvedValue({
+                data: migrationsMockData,
+            } as ActionResult),
+        },
+    };
+
+    test('should match snapshot when there are no migrations', () => {
+        const wrapper = shallow(
+            <MigrationsTable
+                {...baseProps}
+            />);
+
+        expect(wrapper).toMatchSnapshot();
+    });
+
+    test('should have called actions.getAppliedSchemaMigrations only when first rendered', async () => {
+        const mockMigrations = [
+            {version: '1.0', name: 'Initial migration'},
+            {version: '1.1', name: 'Add users table'},
+        ];
+        const withDataProps = {
+            ...baseProps,
+            actions: {
+                getAppliedSchemaMigrations: (jest.fn()).mockResolvedValue({
+                    data: mockMigrations,
+                } as ActionResult),
+            },
+        };
+
+        const view = renderWithContext(<MigrationsTable {...withDataProps}/>);
+
+        await waitFor(() => {
+            expect(withDataProps.actions.getAppliedSchemaMigrations).toHaveBeenCalledTimes(1);
+        });
+
+        act(() => {
+            const newProps = {...withDataProps, className: 'foo'};
+            view.rerender(<MigrationsTable {...newProps}/>);
+        });
+
+        await waitFor(() => {
+            expect(withDataProps.actions.getAppliedSchemaMigrations).toHaveBeenCalledTimes(1);
+            mockMigrations.forEach((migration) => {
+                expect(screen.getByText(migration.version)).toBeInTheDocument();
+                expect(screen.getByText(migration.name)).toBeInTheDocument();
+            });
+        });
+    });
+});

webapp/channels/src/components/admin_console/database/migrations_table.tsx

@@ -2,7 +2,7 @@
 // See LICENSE.txt for license information.
 
 import classNames from 'classnames';
-import React from 'react';
+import React, {useEffect, useMemo, useState} from 'react';
 import {FormattedMessage} from 'react-intl';
 
 import type {SchemaMigration} from '@mattermost/types/admin';
@@ -11,7 +11,7 @@ import type {ActionResult} from 'mattermost-redux/types/actions';
 
 import './migrations_table.scss';
 
-export type Props = {
+type Props = {
     createHelpText: React.ReactElement;
     className?: string;
     actions: {
@@ -19,72 +19,68 @@ export type Props = {
     };
 }
 
-type State = {
-    migrations: SchemaMigration[];
-}
+const MigrationsTable = ({
+    createHelpText,
+    className,
+    actions,
+}: Props) => {
+    const [migrations, setMigrations] = useState<SchemaMigration[]>([]);
 
-class MigrationsTable extends React.PureComponent<Props, State> {
-    constructor(props: Props) {
-        super(props);
-        this.state = {
-            migrations: [],
-        };
-    }
+    useEffect(() => {
+        async function handleGetAppliedSchemaMigrations() {
+            const result: ActionResult = await actions.getAppliedSchemaMigrations();
+            if (result.data) {
+                setMigrations(result.data);
+            }
+        }
 
-    componentDidMount() {
-        this.props.actions.getAppliedSchemaMigrations().then((result) => {
-            this.setState({
-                migrations: result.data,
-            });
-        });
-    }
-
-    render() {
-        const items = this.state.migrations.map((migration) => {
-            return (
-                <tr
-                    key={migration.version}
-                >
-                    <td className='whitespace--nowrap'>{migration.version}</td>
-                    <td className='whitespace--nowrap'>{migration.name}</td>
-                </tr>
-            );
-        });
+        handleGetAppliedSchemaMigrations();
+    }, []);
 
+    const items = useMemo(() => migrations.map((migration) => {
         return (
-            <div className={classNames('MigrationsTable', 'migrations-table__panel', this.props.className)}>
-                <div className='help-text'>
-                    {this.props.createHelpText}
-                </div>
-                <div className='migrations-table__table'>
-                    <table
-                        className='table'
-                        data-testid='migrationsTable'
-                    >
-                        <thead>
-                            <tr>
-                                <th>
-                                    <FormattedMessage
-                                        id='admin.database.migrations_table.version'
-                                        defaultMessage='Version'
-                                    />
-                                </th>
-                                <th>
-                                    <FormattedMessage
-                                        id='admin.database.migrations_table.name'
-                                        defaultMessage='Name'
-                                    />
-                                </th>
-                            </tr>
-                        </thead>
-                        <tbody>
-                            {items}
-                        </tbody>
-                    </table>
-                </div>
-            </div>
+            <tr
+                key={migration.version}
+            >
+                <td className='whitespace--nowrap'>{migration.version}</td>
+                <td className='whitespace--nowrap'>{migration.name}</td>
+            </tr>
         );
-    }
-}
+    }), [migrations]);
 
-export default MigrationsTable;
+    return (
+        <div className={classNames('MigrationsTable', 'migrations-table__panel', className)}>
+            <div className='help-text'>
+                {createHelpText}
+            </div>
+            <div className='migrations-table__table'>
+                <table
+                    className='table'
+                    data-testid='migrationsTable'
+                >
+                    <thead>
+                        <tr>
+                            <th>
+                                <FormattedMessage
+                                    id='admin.database.migrations_table.version'
+                                    defaultMessage='Version'
+                                />
+                            </th>
+                            <th>
+                                <FormattedMessage
+                                    id='admin.database.migrations_table.name'
+                                    defaultMessage='Name'
+                                />
+                            </th>
+                        </tr>
+                    </thead>
+                    <tbody>
+                        {items}
+                    </tbody>
+                </table>
+            </div>
+        </div>
+    );
+};
+
+export default React.memo(MigrationsTable);