@storybook/addon-docs/dist/modern/frameworks/svelte/svelte-docgen-loader.js

Document component usage and properties in Markdown

import svelteDoc from 'sveltedoc-parser';
import dedent from 'ts-dedent';
import * as path from 'path';
import * as fs from 'fs';
import { getOptions } from 'loader-utils';
import { preprocess } from 'svelte/compiler';
import { logger } from '@storybook/node-logger'; // From https://github.com/sveltejs/svelte/blob/8db3e8d0297e052556f0b6dde310ef6e197b8d18/src/compiler/compile/utils/get_name_from_filename.ts
// Copied because it is not exported from the compiler

function getNameFromFilename(filename) {
  if (!filename) return null;
  const parts = filename.split(/[/\\]/).map(encodeURI);

  if (parts.length > 1) {
    const index_match = parts[parts.length - 1].match(/^index(\.\w+)/);

    if (index_match) {
      parts.pop();
      parts[parts.length - 1] += index_match[1];
    }
  }

  const base = parts.pop().replace(/%/g, 'u').replace(/\.[^.]+$/, '').replace(/[^a-zA-Z_$0-9]+/g, '_').replace(/^_/, '').replace(/_$/, '').replace(/^(\d)/, '_$1');

  if (!base) {
    throw new Error(`Could not derive component name from file ${filename}`);
  }

  return base[0].toUpperCase() + base.slice(1);
}
/**
 * webpack loader for sveltedoc-parser
 * @param source raw svelte component
 */


export default async function svelteDocgen(source) {
  // eslint-disable-next-line no-underscore-dangle
  const {
    resource
  } = this._module;
  const svelteOptions = Object.assign({}, getOptions(this));
  const {
    preprocess: preprocessOptions,
    logDocgen = false
  } = svelteOptions;
  let docOptions;

  if (preprocessOptions) {
    const src = fs.readFileSync(resource).toString();
    const {
      code: fileContent
    } = await preprocess(src, preprocessOptions);
    docOptions = {
      fileContent
    };
  } else {
    docOptions = {
      filename: resource
    };
  } // set SvelteDoc options


  const options = Object.assign({}, docOptions, {
    version: 3
  });
  let docgen = '';

  try {
    const componentDoc = await svelteDoc.parse(options); // get filename for source content

    const file = path.basename(resource); // populate filename in docgen

    componentDoc.name = path.basename(file);
    const componentName = getNameFromFilename(resource);
    docgen = dedent`

              ${componentName}.__docgen = ${JSON.stringify(componentDoc)};
              `;
  } catch (error) {
    if (logDocgen) {
      logger.error(error);
    }
  } // inject __docgen prop in svelte component


  const output = source + docgen;
  return output;
}