| /** | |
|  * @author Toru Nagashima <https://github.com/mysticatea> | |
|  * See LICENSE file in root directory for full license. | |
|  */ | |
| import KEYS from "./visitor-keys.js"; | |
| 
 | |
| /** | |
|  * @typedef {import('./visitor-keys.js').VisitorKeys} VisitorKeys | |
|  */ | |
| 
 | |
| // List to ignore keys. | |
| const KEY_BLACKLIST = new Set([ | |
|     "parent", | |
|     "leadingComments", | |
|     "trailingComments" | |
| ]); | |
| 
 | |
| /** | |
|  * Check whether a given key should be used or not. | |
|  * @param {string} key The key to check. | |
|  * @returns {boolean} `true` if the key should be used. | |
|  */ | |
| function filterKey(key) { | |
|     return !KEY_BLACKLIST.has(key) && key[0] !== "_"; | |
| } | |
| 
 | |
| /** | |
|  * Get visitor keys of a given node. | |
|  * @param {object} node The AST node to get keys. | |
|  * @returns {readonly string[]} Visitor keys of the node. | |
|  */ | |
| export function getKeys(node) { | |
|     return Object.keys(node).filter(filterKey); | |
| } | |
| 
 | |
| // Disable valid-jsdoc rule because it reports syntax error on the type of @returns. | |
| // eslint-disable-next-line valid-jsdoc | |
| /** | |
|  * Make the union set with `KEYS` and given keys. | |
|  * @param {VisitorKeys} additionalKeys The additional keys. | |
|  * @returns {VisitorKeys} The union set. | |
|  */ | |
| export function unionWith(additionalKeys) { | |
|     const retv = /** @type {{ | |
|         [type: string]: ReadonlyArray<string> | |
|     }} */ (Object.assign({}, KEYS)); | |
| 
 | |
|     for (const type of Object.keys(additionalKeys)) { | |
|         if (Object.prototype.hasOwnProperty.call(retv, type)) { | |
|             const keys = new Set(additionalKeys[type]); | |
| 
 | |
|             for (const key of retv[type]) { | |
|                 keys.add(key); | |
|             } | |
| 
 | |
|             retv[type] = Object.freeze(Array.from(keys)); | |
|         } else { | |
|             retv[type] = Object.freeze(Array.from(additionalKeys[type])); | |
|         } | |
|     } | |
| 
 | |
|     return Object.freeze(retv); | |
| } | |
| 
 | |
| export { KEYS };
 |