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