radicle-explorer/src/Markdown.svelte

<script lang="ts">
  import { onMount } from "svelte";
  import { marked } from "marked";
  import matter from "@radicle/gray-matter";
  import type * as proj from "@app/project";
  import { getImageMime } from "@app/utils";
  import sanitizeHtml from "sanitize-html";

  export let content: string;
  export let getImage: (path: string) => Promise<proj.Blob>;
  export let doc = matter(content);

  const frontMatter = Object.entries(doc.data);

  let container: HTMLElement;

  const render = (content: string): string => {
    return sanitizeHtml(marked.parse(content), {
      allowedTags: sanitizeHtml.defaults.allowedTags.concat([
        "img",
        "audio",
        "video",
      ]),
      allowedAttributes: {
        ...sanitizeHtml.defaults.allowedAttributes,
        video: ["src"],
        audio: ["src"],
      },
      disallowedTagsMode: "escape",
    });
  };

  onMount(() => {
    // Don't underline <a> tags that contain images.
    let elems = container.querySelectorAll("a");

    for (let e of elems) {
      if (e.firstElementChild instanceof HTMLImageElement) {
        e.classList.add("no-underline");
      }
    }

    // Iterate over all images, and fetch their data from the API, then
    // replace the source with a Data-URL. We do this due to the absence
    // of a static file server.
    for (let i of container.querySelectorAll("img")) {
      const path = i.getAttribute("src");

      if (path) {
        getImage(path).then(blob => {
          if (blob.content) {
            const mime = getImageMime(path);
            if (mime) {
              i.setAttribute("src", `data:${mime};base64,${blob.content}`);
            }
          }
        });
      }
    }
  });
</script>

<style>
  .front-matter {
    font-size: 0.75rem;
    font-family: var(--font-family-monospace);
    color: var(--color-foreground-90);
    border: 1px dashed var(--color-foreground-subtle);
    padding: 0.5rem;
    margin-bottom: 1.5rem;
  }
  .front-matter table {
    border-collapse: collapse;
  }
  .front-matter table td {
    padding: 0.125rem 1rem;
  }
  .front-matter table td:first-child {
    padding-left: 0.5rem;
  }

  .markdown :global(h1), .markdown :global(h2), .markdown :global(h3),
  .markdown :global(h4), .markdown :global(h5), .markdown :global(h6) {
    color: var(--color-foreground);
  }

  .markdown :global(*:first-child) {
    padding-top: 0;
    margin-top: 0;
  }

  .markdown :global(h1) {
    font-family: var(--typeface-medium);
    font-size: 1.5rem;
    font-weight: var(--font-weight-medium);
    padding: 1rem 0 0.5rem 0;
    margin: 0 0 0.75rem;
    border-bottom: 1px solid var(--color-foreground-subtle);
  }

  .markdown :global(h2) {
    font-size: 1.25rem;
    font-weight: normal;
    padding: 0.25rem 0;
    margin: 2rem 0 0.5rem;
    border-bottom: 1px dashed var(--color-foreground-subtle);
  }

  .markdown :global(h3) {
    font-size: 1.125rem;
    font-weight: var(--font-weight-medium);
    padding: 0.5rem 0;
    margin: 1rem 0 0.25rem;
  }

  .markdown :global(h4) {
    font-weight: var(--font-weight-medium);
    font-size: 1rem;
    padding: 0.5rem 0;
    margin: 1rem 0 0.125rem;
  }

  .markdown :global(h5) {
    font-weight: var(--font-weight-medium);
    font-size: 0.875rem;
    padding: 0.35rem 0;
    margin: 1rem 0 0.125rem;
  }

  .markdown :global(h6) {
    font-weight: var(--font-weight-medium);
    font-size: 0.75rem;
    padding: 0.25rem 0;
    margin: 1rem 0 0.125rem;
  }

  .markdown :global(p) {
    line-height: 1.625;
    margin-top: 0;
    margin-bottom: 0.625rem;
  }

  .markdown :global(p:last-child) {
    margin-bottom: 0;
  }

  .markdown :global(blockquote) {
    font-style: italic;
    padding: 0.625rem 0;
    margin: 0;
  }

  .markdown :global(strong) {
    font-weight: var(--font-weight-medium);
  }

  .markdown :global(img) {
    border-style: none;
    max-width: 100%;
  }

  .markdown :global(code) {
    font-family: var(--font-family-monospace);
    font-size: 1rem;
    color: var(--color-light);
  }

  .markdown :global(pre code) {
    background: none;
    padding: 0;
  }

  .markdown :global(pre) {
    font-family: var(--font-family-monospace);
    font-size: 1rem;
    background-color: var(--color-foreground-background);
    padding: 1rem !important;
    border-radius: 0.25rem;
    margin: 1rem 0;
    overflow: scroll;
    scrollbar-width: none;
  }

  .markdown :global(pre::-webkit-scrollbar) {
    display: none;
  }

  .markdown :global(a), .markdown :global(a > code) {
    background: none;
    padding: 0;
    color: var(--color-foreground);
  }
  .markdown :global(a) {
    text-decoration: none;
    border-bottom: 1px solid var(--color-foreground-90);
  }
  .markdown :global(a.no-underline) {
    border-bottom: none;
  }

  .markdown :global(hr) {
    height: 0;
    margin: 0rem 0;
    overflow: hidden;
    background: transparent;
    border: 0;
    border-bottom: 1px solid var(--color-foreground-faded);
  }

  .markdown :global(ol) {
    list-style-type: decimal;
    margin-bottom: 1rem;
    padding-left: 1.5rem;
  }

  .markdown :global(ul) {
    list-style-type: inherit;
    padding-left: 1.25rem;
    margin-bottom: 1rem;
  }
</style>

{#if content}
  {#if frontMatter.length > 0}
    <div class="front-matter">
      <table>
        {#each frontMatter as [key, val]}
          <tr>
            <td><strong>{key}</strong></td>
            <td>{val}</td>
          </tr>
        {/each}
      </table>
    </div>
  {/if}

  <div class="markdown" bind:this={container}>
    {@html render(doc.content)}
  </div>
{/if}