如何修复此ESLint / JSDoc语法错误？

Question

I've documented this function...

/**
 * Perform an asynchronous HTTP (Ajax) request.
 * 
 * @param {String|Object} url A string containing the URL to which the request is sent, or the settings object.
 * @param {Object=} settings A set of key/value pairs that configure the Ajax request. All settings are optional.
 * @param {Object=} settings.accepts A set of key/value pairs that map a given `dataType` to its MIME type, which gets sent in the Accept request header. This header tells the server what kind of response it will accept in return.
 * @param {Boolean=} settings.async By default, all requests are sent asynchronously (i.e. this is set to true by default). If you need synchronous requests, set this option to false.
 * @param {Function=} settings.beforeSend A pre-request callback function that can be used to modify the jqXHR.
 * @param {Boolean=} settings.cache If set to false, it will force requested pages not to be cached by the browser.
 * @param {Function=} settings.complete A function to be called when the request finishes (after success and error callbacks are executed).
 * @param {Object=} settings.contents An object of string/regular-expression pairs that determine how jQuery will parse the response, given its content type.
 * @param {Boolean|String=} settings.contentType When sending data to the server, use this content type. Default is "application/x-www-form-urlencoded; charset=UTF-8", which is fine for most cases.
 * @param {Object=} settings.context This object will be the context of all Ajax-related callbacks.
 * @param {Object=} settings.converters An object containing dataType-to-dataType converters. Each converter's value is a function that returns the transformed value of the response.
 * @param {Boolean=} settings.crossDomain If you wish to force a crossDomain request (such as JSONP) on the same domain, set the value of crossDomain to true. This allows, for example, server-side redirection to another domain.
 * @param {Object|String|Array=} settings.data  Data to be sent to the server. It is converted to a query string, if not already a string. It's appended to the url for GET-requests.
 * @param {Function=} settings.dataFilter A function to be used to handle the raw response data of XMLHttpRequest. This is a pre-filtering function to sanitize the response. You should return the sanitized data. The function accepts two arguments: The raw data returned from the server and the 'dataType' parameter.
 * @param {String=json} settings.dataType The type of data that you're expecting back from the server. If none is specified, jQuery will try to infer it based on the MIME type of the response.
 * @param {Function=} settings.error A function to be called if the request fails.
 * @param {Boolean=true} settings.global Whether to trigger global Ajax event handlers for this request.
 * @param {Object=} settings.headers An object of additional header key/value pairs to send along with requests using the XMLHttpRequest transport.
 * @param {Boolean=false} settings.ifModified Allow the request to be successful only if the response has changed since the last request. This is done by checking the Last-Modified header.
 * @param {Boolean=} settings.isLocal Allow the current environment to be recognized as "local," (e.g. the filesystem), even if jQuery does not recognize it as such by default.
 * @param {String|Boolean=} settings.jsonp Override the callback function name in a JSONP request.
 * @param {String|Function=} settings.jsonpCallback Specify the callback function name for a JSONP request.
 * @param {String=GET} settings.method The HTTP method to use for the request (e.g. "POST", "GET", "PUT").
 * @param {String=} settings.mimeType A mime type to override the XHR mime type.
 * @param {String=} settings.password A password to be used with XMLHttpRequest in response to an HTTP access authentication request.
 * @param {Boolean=true} settings.processData By default, data passed in to the data option as an object (technically, anything other than a string) will be processed and transformed into a query string, fitting to the default content-type "application/x-www-form-urlencoded". If you want to send a DOMDocument, or other non-processed data, set this option to false.
 * @param {String=} settings.scriptCharset Only applies when the "script" transport is used (e.g., cross-domain requests with "jsonp" or "script" dataType and "GET" type). Sets the charset attribute on the script tag used in the request. Used when the character set on the local page is not the same as the one on the remote script.
 * @param {Object=} settings.statusCode An object of numeric HTTP codes and functions to be called when the response has the corresponding code.
 * @param {Function=} settings.success A function to be called if the request succeeds.
 * @param {Number=} settings.timeout Set a timeout (in milliseconds) for the request.
 * @param {Boolean=} settings.traditional Set this to true if you wish to use the traditional style of param serialization.
 * @param {String=GET} settings.type An alias for method. A string containing the URL to which the request is sent.
 * @param {String|Object=} settings.url A string containing the URL to which the request is sent, or an object to be sent to `wxu.link()`.
 * @param {String=} settings.username A username to be used with XMLHttpRequest in response to an HTTP access authentication request.
 * @param {Function=} settings.xhr Callback for creating the XMLHttpRequest object.
 * @param {Object=} settings.xhrFields An object of fieldName-fieldValue pairs to set on the native XHR object.
 * @returns {Promise.<Object>} Resolved when XHR request completes with 2xx status code, rejects otherwise
 * @see https://api.jquery.com/jquery.ajax/
 */
export default function ajax(url, settings = {}) {
    // *snip*
}

But eslint is giving me this error:

JSDoc syntax error

Nothing more. I have no idea where the error is. Is there a tool for validating JSDocs that will give me a precise line/column number? Or can someone spot the problem?

I have another function documented in a similar fashion (with all options documented), and that one is lint-free, so I thought this format was acceptable.

Answer 1

ESLint uses Doctrine to parse JSDoc comments. In case parsing fails, ESLint outputs whatever parser returned. You can try to use Doctrine directly on your JSDoc code, and see if it will be able to provide more meaningful error.

Answer 2

Through much trial and error, it appears that Doctrine doesn't like the default values on the arguments.

var doctrine = require("doctrine");

let doc = `
/**
 * Perform an asynchronous HTTP (Ajax) request.
 * 
 * @param {String|Object} url A string containing the URL to which the request is sent, or the settings object.
 * @param {Object=} settings A set of key/value pairs that configure the Ajax request. All settings are optional.
 * @param {Object=} settings.accepts A set of key/value pairs that map a given \`dataType\` to its MIME type, which gets sent in the Accept request header. This header tells the server what kind of response it will accept in return.
 * @param {Boolean=} settings.async By default, all requests are sent asynchronously (i.e. this is set to true by default). If you need synchronous requests, set this option to false.
 * @param {Function=} settings.beforeSend A pre-request callback function that can be used to modify the jqXHR.
 * @param {Boolean=} settings.cache If set to false, it will force requested pages not to be cached by the browser.
 * @param {Function=} settings.complete A function to be called when the request finishes (after success and error callbacks are executed).
 * @param {Object=} settings.contents An object of string/regular-expression pairs that determine how jQuery will parse the response, given its content type.
 * @param {Boolean|String=} settings.contentType When sending data to the server, use this content type. Default is "application/x-www-form-urlencoded; charset=UTF-8", which is fine for most cases.
 * @param {Object=} settings.context This object will be the context of all Ajax-related callbacks.
 * @param {Object=} settings.converters An object containing dataType-to-dataType converters. Each converter's value is a function that returns the transformed value of the response.
 * @param {Boolean=} settings.crossDomain If you wish to force a crossDomain request (such as JSONP) on the same domain, set the value of crossDomain to true. This allows, for example, server-side redirection to another domain.
 * @param {Object|String|Array=} settings.data  Data to be sent to the server. It is converted to a query string, if not already a string. It's appended to the url for GET-requests.
 * @param {Function=} settings.dataFilter A function to be used to handle the raw response data of XMLHttpRequest. This is a pre-filtering function to sanitize the response. You should return the sanitized data. The function accepts two arguments: The raw data returned from the server and the 'dataType' parameter.
 * @param {String=json} settings.dataType The type of data that you're expecting back from the server. If none is specified, jQuery will try to infer it based on the MIME type of the response.
 * @param {Function=} settings.error A function to be called if the request fails.
 * @param {Boolean=true} settings.global Whether to trigger global Ajax event handlers for this request.
 * @param {Object=} settings.headers An object of additional header key/value pairs to send along with requests using the XMLHttpRequest transport.
 * @param {Boolean=false} settings.ifModified Allow the request to be successful only if the response has changed since the last request. This is done by checking the Last-Modified header.
 * @param {Boolean=} settings.isLocal Allow the current environment to be recognized as "local," (e.g. the filesystem), even if jQuery does not recognize it as such by default.
 * @param {String|Boolean=} settings.jsonp Override the callback function name in a JSONP request.
 * @param {String|Function=} settings.jsonpCallback Specify the callback function name for a JSONP request.
 * @param {String=} settings.mimeType A mime type to override the XHR mime type.
 * @param {String=} settings.password A password to be used with XMLHttpRequest in response to an HTTP access authentication request.
 * @param {Boolean=true} settings.processData By default, data passed in to the data option as an object (technically, anything other than a string) will be processed and transformed into a query string, fitting to the default content-type "application/x-www-form-urlencoded". If you want to send a DOMDocument, or other non-processed data, set this option to false.
 * @param {String=} settings.scriptCharset Only applies when the "script" transport is used (e.g., cross-domain requests with "jsonp" or "script" dataType and "GET" type). Sets the charset attribute on the script tag used in the request. Used when the character set on the local page is not the same as the one on the remote script.
 * @param {Object=} settings.statusCode An object of numeric HTTP codes and functions to be called when the response has the corresponding code.
 * @param {Function=} settings.success A function to be called if the request succeeds.
 * @param {Number=} settings.timeout Set a timeout (in milliseconds) for the request.
 * @param {Boolean=} settings.traditional Set this to true if you wish to use the traditional style of param serialization.
 * @param {String=GET} settings.type An alias for method. A string containing the URL to which the request is sent.
 * @param {String|Object=} settings.url A string containing the URL to which the request is sent, or an object to be sent to \`wxu.link()\`.
 * @param {String=} settings.username A username to be used with XMLHttpRequest in response to an HTTP access authentication request.
 * @param {Function=} settings.xhr Callback for creating the XMLHttpRequest object.
 * @param {Object=} settings.xhrFields An object of fieldName-fieldValue pairs to set on the native XHR object.
 * @returns {Promise.<Object>} Resolved when XHR request completes with 2xx status code, rejects otherwise
 * @see https://api.jquery.com/jquery.ajax/
 */
`;

var ast = doctrine.parse(doc, {unwrap: true, recoverable: false});

var util = require('util');

console.log(util.inspect(ast.tags.map(t => ([t.title, t.name])), {depth: 5, colors: true}));

This outputs:

[ [ 'param', 'url' ],
  [ 'param', 'settings' ],
  [ 'param', 'settings.accepts' ],
  [ 'param', 'settings.async' ],
  [ 'param', 'settings.beforeSend' ],
  [ 'param', 'settings.cache' ],
  [ 'param', 'settings.complete' ],
  [ 'param', 'settings.contents' ],
  [ 'param', 'settings.contentType' ],
  [ 'param', 'settings.context' ],
  [ 'param', 'settings.converters' ],
  [ 'param', 'settings.crossDomain' ],
  [ 'param', 'settings.data' ],
  [ 'param', 'settings.dataFilter' ] ]

Removing all the default values lets it finish parsing. I can't figure out how to specify the default values using the square bracket around the parameter name syntax, so I guess this will have to do.