Class to functional component example 1 (#24181)

* Class to functional component example 1

* Fix lint and tests

* Fix

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

webapp/channels/src/components/__snapshots__/textbox.test.tsx.snap

@@ -36,8 +36,24 @@ exports[`components/TextBox should match snapshot with required props 1`] = `
     id="someid"
     inputComponent={
       Object {
-        "$$typeof": Symbol(react.forward_ref),
-        "render": [Function],
+        "$$typeof": Symbol(react.memo),
+        "compare": null,
+        "type": Object {
+          "$$typeof": Symbol(react.forward_ref),
+          "propTypes": Object {
+            "className": [Function],
+            "defaultValue": [Function],
+            "disabled": [Function],
+            "id": [Function],
+            "onChange": [Function],
+            "onHeightChange": [Function],
+            "onInput": [Function],
+            "onWidthChange": [Function],
+            "placeholder": [Function],
+            "value": [Function],
+          },
+          "render": [Function],
+        },
       }
     }
     listComponent={[Function]}
@@ -127,8 +143,24 @@ exports[`components/TextBox should throw error when new property is too long 1`]
     id="someid"
     inputComponent={
       Object {
-        "$$typeof": Symbol(react.forward_ref),
-        "render": [Function],
+        "$$typeof": Symbol(react.memo),
+        "compare": null,
+        "type": Object {
+          "$$typeof": Symbol(react.forward_ref),
+          "propTypes": Object {
+            "className": [Function],
+            "defaultValue": [Function],
+            "disabled": [Function],
+            "id": [Function],
+            "onChange": [Function],
+            "onHeightChange": [Function],
+            "onInput": [Function],
+            "onWidthChange": [Function],
+            "placeholder": [Function],
+            "value": [Function],
+          },
+          "render": [Function],
+        },
       }
     }
     listComponent={[Function]}
@@ -218,8 +250,24 @@ exports[`components/TextBox should throw error when value is too long 1`] = `
     id="someid"
     inputComponent={
       Object {
-        "$$typeof": Symbol(react.forward_ref),
-        "render": [Function],
+        "$$typeof": Symbol(react.memo),
+        "compare": null,
+        "type": Object {
+          "$$typeof": Symbol(react.forward_ref),
+          "propTypes": Object {
+            "className": [Function],
+            "defaultValue": [Function],
+            "disabled": [Function],
+            "id": [Function],
+            "onChange": [Function],
+            "onHeightChange": [Function],
+            "onInput": [Function],
+            "onWidthChange": [Function],
+            "placeholder": [Function],
+            "value": [Function],
+          },
+          "render": [Function],
+        },
       }
     }
     listComponent={[Function]}

webapp/channels/src/components/autosize_textarea.test.tsx

@@ -4,7 +4,7 @@
 import {shallow} from 'enzyme';
 import React from 'react';
 
-import {AutosizeTextarea} from 'components/autosize_textarea';
+import AutosizeTextarea from 'components/autosize_textarea';
 
 describe('components/AutosizeTextarea', () => {
     test('should match snapshot, init', () => {

webapp/channels/src/components/autosize_textarea.tsx

@@ -1,8 +1,10 @@
 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.
 
-import React from 'react';
-import type {ChangeEvent, FormEvent, CSSProperties} from 'react';
+import type {ChangeEvent, FormEvent, HTMLProps} from 'react';
+import React, {useRef, useEffect, useCallback} from 'react';
+
+import type {Intersection} from '@mattermost/types/utilities';
 
 type Props = {
     id?: string;
@@ -15,191 +17,173 @@ type Props = {
     onWidthChange?: (width: number) => void;
     onInput?: (e: FormEvent<HTMLTextAreaElement>) => void;
     placeholder?: string;
-    forwardedRef?: ((instance: HTMLTextAreaElement | null) => void) | React.MutableRefObject<HTMLTextAreaElement | null> | null;
-}
+} & Intersection<HTMLProps<HTMLTextAreaElement>, HTMLProps<HTMLDivElement>>;
 
-export class AutosizeTextarea extends React.PureComponent<Props> {
-    private height: number;
+const styles = {
+    container: {
+        height: 0,
+        overflow: 'hidden',
+    },
+    reference: {
+        display: 'inline-block',
+        height: 'auto',
+        width: 'auto',
+    },
+    placeholder: {
+        overflow: 'hidden',
+        textOverflow: 'ellipsis',
+        opacity: 0.5,
+        pointerEvents: 'none' as const,
+        position: 'absolute' as const,
+        whiteSpace: 'nowrap' as const,
+        background: 'none',
+        borderColor: 'transparent',
+    },
+};
 
-    private textarea?: HTMLTextAreaElement;
-    private referenceRef: React.RefObject<HTMLDivElement>;
+const AutosizeTextarea = React.forwardRef<HTMLTextAreaElement, Props>(({
 
-    constructor(props: Props) {
-        super(props);
+    // TODO: The provided `id` is sometimes hard-coded and used to interface with the
+    // component, e.g. `post_textbox`, so it can't be changed. This would ideally be
+    // abstracted to avoid passing in an `id` prop at all, but we intentionally maintain
+    // the old behaviour to address ABC-213.
+    id = 'autosize_textarea',
+    disabled,
+    value,
+    defaultValue,
+    onChange,
+    onHeightChange,
+    onWidthChange,
+    onInput,
+    placeholder,
+    ...otherProps
+}: Props, ref) => {
+    const height = useRef(0);
+    const textarea = useRef<HTMLTextAreaElement>();
+    const referenceRef = useRef<HTMLDivElement>(null);
 
-        this.height = 0;
-
-        this.referenceRef = React.createRef();
-    }
-
-    componentDidMount() {
-        this.recalculateHeight();
-        this.recalculateWidth();
-    }
-
-    componentDidUpdate() {
-        this.recalculateHeight();
-        this.recalculateWidth();
-    }
-
-    private recalculateHeight = () => {
-        if (!this.referenceRef.current || !this.textarea) {
+    const recalculateHeight = () => {
+        if (!referenceRef.current || !textarea.current) {
             return;
         }
 
-        const height = (this.referenceRef.current).scrollHeight;
-        const textarea = this.textarea;
+        const scrollHeight = referenceRef.current.scrollHeight;
+        const currentTextarea = textarea.current;
 
-        if (height > 0 && height !== this.height) {
-            const style = getComputedStyle(textarea);
+        if (scrollHeight > 0 && scrollHeight !== height.current) {
+            const style = getComputedStyle(currentTextarea);
 
             // Directly change the height to avoid circular rerenders
-            textarea.style.height = `${height}px`;
+            currentTextarea.style.height = `${scrollHeight}px`;
 
-            this.height = height;
+            height.current = scrollHeight;
 
-            this.props.onHeightChange?.(height, parseInt(style.maxHeight || '0', 10));
+            onHeightChange?.(scrollHeight, parseInt(style.maxHeight || '0', 10));
         }
     };
 
-    private recalculateWidth = () => {
-        if (!this.referenceRef) {
+    const recalculateWidth = () => {
+        if (!referenceRef.current) {
             return;
         }
 
-        const width = this.referenceRef.current?.offsetWidth || -1;
+        const width = referenceRef.current?.offsetWidth || -1;
         if (width >= 0) {
             window.requestAnimationFrame(() => {
-                this.props.onWidthChange?.(width);
+                onWidthChange?.(width);
             });
         }
     };
 
-    private setTextareaRef = (textarea: HTMLTextAreaElement) => {
-        if (this.props.forwardedRef) {
-            if (typeof this.props.forwardedRef === 'function') {
-                this.props.forwardedRef(textarea);
+    const setTextareaRef = useCallback((textareaRef: HTMLTextAreaElement) => {
+        if (ref) {
+            if (typeof ref === 'function') {
+                ref(textareaRef);
             } else {
-                this.props.forwardedRef.current = textarea;
+                ref.current = textareaRef;
             }
         }
 
-        this.textarea = textarea;
+        textarea.current = textareaRef;
+    }, [ref]);
+
+    useEffect(() => {
+        recalculateHeight();
+        recalculateWidth();
+    });
+
+    const heightProps = {
+        rows: 0,
+        height: 0,
     };
 
-    render() {
-        const props = {...this.props};
+    if (height.current <= 0) {
+        // Set an initial number of rows so that the textarea doesn't appear too large when its first rendered
+        heightProps.rows = 1;
+    } else {
+        heightProps.height = height.current;
+    }
 
-        Reflect.deleteProperty(props, 'onHeightChange');
-        Reflect.deleteProperty(props, 'providers');
-        Reflect.deleteProperty(props, 'channelId');
-        Reflect.deleteProperty(props, 'forwardedRef');
-
-        const {
-            value,
-            defaultValue,
-            placeholder,
-            disabled,
-            onInput,
-
-            // TODO: The provided `id` is sometimes hard-coded and used to interface with the
-            // component, e.g. `post_textbox`, so it can't be changed. This would ideally be
-            // abstracted to avoid passing in an `id` prop at all, but we intentionally maintain
-            // the old behaviour to address ABC-213.
-            id = 'autosize_textarea',
-            ...otherProps
-        } = props;
-
-        const heightProps = {
-            rows: 0,
-            height: 0,
-        };
-
-        Reflect.deleteProperty(otherProps, 'onWidthChange');
-
-        if (this.height <= 0) {
-            // Set an initial number of rows so that the textarea doesn't appear too large when its first rendered
-            heightProps.rows = 1;
-        } else {
-            heightProps.height = this.height;
-        }
-
-        let textareaPlaceholder = null;
-        const placeholderAriaLabel = placeholder ? placeholder.toLowerCase() : '';
-        if (!this.props.value && !this.props.defaultValue) {
-            textareaPlaceholder = (
-                <div
-                    {...otherProps as any}
-                    id={`${id}_placeholder`}
-                    data-testid={`${id}_placeholder`}
-                    style={styles.placeholder}
-                >
-                    {placeholder}
-                </div>
-            );
-        }
-
-        let referenceValue = value || defaultValue;
-        if (referenceValue?.endsWith('\n')) {
-            // In a div, the browser doesn't always count characters at the end of a line when measuring the dimensions
-            // of text. In the spec, they refer to those characters as "hanging". No matter what value we set for the
-            // `white-space` of a div, a single newline at the end of the div will always hang.
-            //
-            // The textarea doesn't have that behaviour, so we need to trick the reference div into measuring that
-            // newline, and it seems like the best way to do that is by adding a second newline because only the final
-            // one hangs.
-            referenceValue += '\n';
-        }
-
-        return (
-            <div>
-                {textareaPlaceholder}
-                <textarea
-                    ref={this.setTextareaRef}
-                    data-testid={id}
-                    id={id}
-                    {...heightProps}
-                    {...otherProps}
-                    role='textbox'
-                    aria-label={placeholderAriaLabel}
-                    dir='auto'
-                    disabled={disabled}
-                    onChange={this.props.onChange}
-                    onInput={onInput}
-                    value={value}
-                    defaultValue={defaultValue}
-                />
-                <div style={styles.container}>
-                    <div
-                        ref={this.referenceRef}
-                        id={id + '-reference'}
-                        className={otherProps.className}
-                        style={styles.reference}
-                        dir='auto'
-                        disabled={true}
-                        aria-hidden={true}
-                    >
-                        {referenceValue}
-                    </div>
-                </div>
+    let textareaPlaceholder = null;
+    const placeholderAriaLabel = placeholder ? placeholder.toLowerCase() : '';
+    if (!value && !defaultValue) {
+        textareaPlaceholder = (
+            <div
+                {...otherProps}
+                id={`${id}_placeholder`}
+                data-testid={`${id}_placeholder`}
+                style={styles.placeholder}
+            >
+                {placeholder}
             </div>
         );
     }
-}
 
-const styles: { [Key: string]: CSSProperties} = {
-    container: {height: 0, overflow: 'hidden'},
-    reference: {display: 'inline-block', height: 'auto', width: 'auto'},
-    placeholder: {overflow: 'hidden', textOverflow: 'ellipsis', opacity: 0.5, pointerEvents: 'none', position: 'absolute', whiteSpace: 'nowrap', background: 'none', borderColor: 'transparent'},
-};
+    let referenceValue = value || defaultValue;
+    if (referenceValue?.endsWith('\n')) {
+        // In a div, the browser doesn't always count characters at the end of a line when measuring the dimensions
+        // of text. In the spec, they refer to those characters as "hanging". No matter what value we set for the
+        // `white-space` of a div, a single newline at the end of the div will always hang.
+        //
+        // The textarea doesn't have that behaviour, so we need to trick the reference div into measuring that
+        // newline, and it seems like the best way to do that is by adding a second newline because only the final
+        // one hangs.
+        referenceValue += '\n';
+    }
 
-const forwarded = React.forwardRef<HTMLTextAreaElement>((props, ref) => (
-    <AutosizeTextarea
-        forwardedRef={ref}
-        {...props}
-    />
-));
+    return (
+        <div>
+            {textareaPlaceholder}
+            <textarea
+                ref={setTextareaRef}
+                data-testid={id}
+                id={id}
+                {...heightProps}
+                {...otherProps}
+                role='textbox'
+                aria-label={placeholderAriaLabel}
+                dir='auto'
+                disabled={disabled}
+                onChange={onChange}
+                onInput={onInput}
+                value={value}
+                defaultValue={defaultValue}
+            />
+            <div style={styles.container}>
+                <div
+                    ref={referenceRef}
+                    id={id + '-reference'}
+                    className={otherProps.className}
+                    style={styles.reference}
+                    dir='auto'
+                    disabled={true}
+                    aria-hidden={true}
+                >
+                    {referenceValue}
+                </div>
+            </div>
+        </div>
+    );
+});
 
-forwarded.displayName = 'AutosizeTextarea';
-
-export default forwarded;
+export default React.memo(AutosizeTextarea);

webapp/channels/src/components/common/hooks/useDidUpdate.ts

@@ -0,0 +1,20 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+// Disable consistent return since the effectCallback allows for non consistent returns.
+/* eslint-disable consistent-return */
+
+import {useEffect, useRef} from 'react';
+
+const useDidUpdate: typeof useEffect = (effect, deps) => {
+    const mounted = useRef(false);
+    useEffect(() => {
+        if (mounted.current) {
+            return effect();
+        }
+
+        mounted.current = true;
+    }, deps);
+};
+
+export default useDidUpdate;

webapp/platform/types/src/utilities.ts

@@ -24,3 +24,6 @@ export type ValueOf<T> = T[keyof T];
  */
 export type RequireOnlyOne<T, Keys extends keyof T = keyof T> =
 Pick<T, Exclude<keyof T, Keys>> & {[K in Keys]-?: Required<Pick<T, K>> & Partial<Record<Exclude<Keys, K>, undefined>>}[Keys];
+
+export type Intersection<T1, T2> =
+Omit<Omit<T1&T2, keyof(Omit<T1, keyof(T2)>)>, keyof(Omit<T2, keyof(T1)>)>;