starlight-ion-theme/components/utils/createPathFormatter.ts


import type { AstroConfig } from "astro";

import { fileWithBase, pathWithBase } from "./base";
import {
  ensureHtmlExtension,
  ensureTrailingSlash,
  stripHtmlExtension,
  stripTrailingSlash,
} from "./path";

interface FormatPathOptions {
  format?: AstroConfig["build"]["format"];
  trailingSlash?: AstroConfig["trailingSlash"];
}

const formatStrategies: {
  [key: string]: {
    addBase: Function;
    handleExtension: (href: string) => string;
  };
} = {
  file: {
    addBase: fileWithBase,
    handleExtension: (href: string) => ensureHtmlExtension(href),
  },
  directory: {
    addBase: pathWithBase,
    handleExtension: (href: string) => stripHtmlExtension(href),
  },
};

const trailingSlashStrategies = {
  always: ensureTrailingSlash,
  never: stripTrailingSlash,
  ignore: (href: string) => href,
};

/** Format a path based on the project config. */
function formatPath(
  href: string,
  { format = "directory", trailingSlash = "ignore" }: FormatPathOptions
) {
  const formatStrategy = formatStrategies[format];
  const trailingSlashStrategy = trailingSlashStrategies[trailingSlash];

  // Add base
  href = formatStrategy.addBase(href);

  // Handle extension
  href = formatStrategy.handleExtension(href);

  // Skip trailing slash handling for `build.format: 'file'`
  if (format === "file") return href;

  // Handle trailing slash
  href = href === "/" ? href : trailingSlashStrategy(href);

  return href;
}

export function createPathFormatter(opts: FormatPathOptions) {
  return (href: string) => formatPath(href, opts);
}