signal-desktop/ts/components/conversation/Emojify.tsx

// Copyright 2018-2021 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only

import React from 'react';

import classNames from 'classnames';

import type { RenderTextCallbackType } from '../../types/Util';
import { splitByEmoji } from '../../util/emoji';
import { missingCaseError } from '../../util/missingCaseError';
import type { SizeClassType } from '../emoji/lib';
import { emojiToImage } from '../emoji/lib';

// Some of this logic taken from emoji-js/replacement
// the DOM structure for this getImageTag should match the other emoji implementations:
// ts/components/emoji/Emoji.tsx
// ts/quill/emoji/blot.tsx
function getImageTag({
  match,
  sizeClass,
  key,
}: {
  match: string;
  sizeClass?: SizeClassType;
  key: string | number;
}): JSX.Element | string {
  const img = emojiToImage(match);

  if (!img) {
    return match;
  }

  return (
    <img
      key={key}
      src={img}
      aria-label={match}
      className={classNames('emoji', sizeClass)}
      alt={match}
    />
  );
}

export type Props = {
  text: string;
  /** A class name to be added to the generated emoji images */
  sizeClass?: SizeClassType;
  /** Allows you to customize now non-newlines are rendered. Simplest is just a <span>. */
  renderNonEmoji?: RenderTextCallbackType;
};

export class Emojify extends React.Component<Props> {
  public static defaultProps: Partial<Props> = {
    renderNonEmoji: ({ text }) => text,
  };

  public override render(): null | Array<JSX.Element | string | null> {
    const { text, sizeClass, renderNonEmoji } = this.props;

    // We have to do this, because renderNonEmoji is not required in our Props object,
    //  but it is always provided via defaultProps.
    if (!renderNonEmoji) {
      return null;
    }

    return splitByEmoji(text).map(({ type, value: match }, index) => {
      if (type === 'emoji') {
        return getImageTag({ match, sizeClass, key: index });
      }

      if (type === 'text') {
        return renderNonEmoji({ text: match, key: index });
      }

      throw missingCaseError(type);
    });
  }
}