A Turndown Plugin parsing figures with captions; creates the format '' Turndown is a JS Markdown Parser see https://www.npmjs.com/package/turndown

plugin-so-turndown.ts

export const figureCaption = function (service: TurndownService): void {
    service.addRule('stackOverflowHighlightedCodeBlock', {
        filter: function (node: HTMLElement, options: Options): boolean | null {
            const firstChild = node.firstChild
            const lastChild = node.lastChild
            return (
                node.nodeName === 'FIGURE' &&
                firstChild && firstChild.nodeName === 'IMG' &&
                lastChild && lastChild.nodeName === 'FIGCAPTION'
            )
        } as Filter,
        replacement: function (content: string, node: HTMLElement, options: Options): string {
            const imgNode = node.firstChild as HTMLImageElement;
            const captionNode = node.lastChild

            const altText = imgNode.alt
            const imgSrc = imgNode.src
            const caption = captionNode!.textContent

            return (
                `![${altText}](${imgSrc + ' '}"${caption}")\n`
            )
        } as ReplacementFunction
    })
} as TurndownService.Plugin

test.ts

import TurndownService from "turndown";

describe('figureCaption', () => {
    let turndownService: TurndownService;

    beforeEach(() => {
        turndownService = new TurndownService();
        turndownService.use(figureCaption);
    });

    it('should convert figure with img and figcaption to markdown', () => {
        const inputHTML = `
      <figure>
        <img src="example.png" alt="Example image">
        <figcaption>Example caption</figcaption>
      </figure>
    `;
        const expectedMarkdown = '![Example image](/example.png "Example caption")';
        const result = turndownService.turndown(inputHTML);

        expect(result).toEqual(expectedMarkdown);
    });

    it('should not affect other elements', () => {
        const inputHTML = `
      <p>Some text</p>
      <img src="another-example.png" alt="Another example">
    `;

        const expectedMarkdown = 'Some text\n\n![Another example](another-example.png)';
        const result = turndownService.turndown(inputHTML);

        expect(result).toEqual(expectedMarkdown);
    });
});