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// @ts-check
/** * Asserts a value is a standard import map. * @see https://wicg.github.io/import-maps/#parsing * @param {any} value Supposed import map. * @returns {asserts value is ImportMap} `void` for JavaScript and the assertion *   for TypeScript. */export default function assertImportMap(value) {  try {    // Todo: Deeper validation of URL strings, etc.
    if (typeof value !== "object" || !value) {      throw new TypeError("Import map must be an object.");    }
    if ("imports" in value) {      if (typeof value.imports !== "object" || !value.imports) {        throw new TypeError("Import map property `imports` must be an object.");      }
      for (const [importsKey, importsValue] of Object.entries(value.imports)) {        if (!importsKey.length) {          throw new TypeError(            `Import map property \`imports\` mustn’t contain an empty key.`,          );        }
        if (typeof importsValue !== "string") {          throw new TypeError(            `Import map property \`imports\` property \`${importsKey}\` must be a string.`,          );        }
        if (!importsValue.length) {          throw new TypeError(            `Import map property \`imports\` property \`${importsKey}\` must be a non empty string.`,          );        }      }    }
    if ("scopes" in value) {      if (typeof value.scopes !== "object" || !value.scopes) {        throw new TypeError("Import map property `scopes` must be an object.");      }
      for (const [scopesKey, scopesValue] of Object.entries(value.scopes)) {        if (!scopesKey.length) {          throw new TypeError(            `Import map property \`scopes\` mustn’t contain an empty key.`,          );        }
        if (typeof scopesValue !== "object" || !scopesValue) {          throw new TypeError(            `Import map property \`scopes\` property \`${scopesKey}\` must be an object.`,          );        }
        for (const [scopeKey, scopeValue] of Object.entries(scopesValue)) {          if (!scopeKey.length) {            throw new TypeError(              `Import map property \`scopes\` property \`${scopesKey}\` mustn’t contain an empty key.`,            );          }
          if (typeof scopeValue !== "string") {            throw new TypeError(              `Import map property \`scopes\` property \`${scopesKey}\` property \`${scopeKey}\` must be a string.`,            );          }
          if (!scopeValue.length) {            throw new TypeError(              `Import map property \`scopes\` property \`${scopesKey}\` property \`${scopeKey}\` must be a non empty string.`,            );          }        }      }    }  } catch (cause) {    throw new TypeError("Invalid import map.", { cause });  }}
/** * A standard import map. * @see https://github.com/WICG/import-maps * @typedef {object} ImportMap * @prop {ImportMapSpecifierMap} [imports] Import specifier map. * @prop {Record<string, ImportMapSpecifierMap>} [scopes] Ordered map of URLs *   to import specifier maps. */
/** * Ordered map of import specifiers to absolute or relative URL addresses. * @typedef {Record<string, string>} ImportMapSpecifierMap */