git.squeep.com Git - squeep-api-dingus/blob - lib/router/path-parameter.js

   1 'use strict';
   2
   3 const parameters = new Map();
   4 /**
   5  * De-duplicating factory of minimal-objects to track the named-parameter parts of path definitions.
   6  *
   7  * @property {String} parameter
   8  */
   9 class PathParameter extends null {
  10   constructor(parameter) {
  11     if (!parameter || typeof(parameter) !== 'string') {
  12       throw new RangeError('parameter must be string');
  13     }
  14     if (parameters.has(parameter)) {
  15       return parameters.get(parameter);
  16     }
  17     const pathParameter = Object.create(PathParameter.prototype);
  18     pathParameter.parameter = parameter;
  19     parameters.set(parameter, pathParameter);
  20     Object.freeze(pathParameter);
  21     return pathParameter;
  22   }
  23
  24   /**
  25    * @returns {String}
  26    */
  27   toString() {
  28     return `{${this.constructor.name} ${this.parameter}}`;
  29   }
  30
  31   /**
  32    * Clear the de-duplication table, for tests.
  33    */
  34   static _flush() {
  35     this.parameters.clear();
  36   }
  37 }
  38 PathParameter.parameters = parameters;
  39
  40 module.exports = PathParameter;