packages/range/src/index.js

/**
 * @license
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

import { product } from './cartesian.js';

export function createRangeSelectorCreator(createSelector) {
  return function createRangeSelector(selector) {
    const startSelector = createSelector(selector.startSelector);
    const endSelector = createSelector(selector.endSelector);

    return async function* matchAll(scope) {
      const startMatches = startSelector(scope);
      const endMatches = endSelector(scope);
      const pairs = product(startMatches, endMatches);
      for await (let [start, end] of pairs) {
        if (start.index > end.index) {
          continue;
        }
        const text = rangeBetween({ start, end, scope });
        const result = [text];
        result.index = start.index;
        result.input = scope;
        yield result;
      }
    };
  };
}

function rangeBetween({ start, end, scope }) {
  const range = scope.substring(start.index, end.index);
  return range;
}