1  "use strict";
 2  Object.defineProperty(exports, "__esModule", { value: true });
 3  exports.RewindableValue = void 0;
 4  const clone_1 = require("./clone");
 5  /* eslint-disable no-underscore-dangle */
 6  /**
 7   * A lightweight wrapper around a primitive value which allows its state
 8   * to saved and later restored.
 9   */
10  class RewindableValue {
11      /**
12       * Create a rewindable value.
13       *
14       * @param initialValue - The initial value for the new instance.
15       */
16      constructor(initialValue) {
17          this._values = [initialValue];
18      }
19      /**
20       * Returns the current value of this instance.
21       */
22      get() {
23          return this._values[this._values.length - 1];
24      }
25      /**
26       * Replace the current value of this instance.
27       *
28       * @param newValue - The value to assign this instance.
29       */
30      set(newValue) {
31          this._values[this._values.length - 1] = newValue;
32      }
33      /**
34       * Save the current state of this value.
35       *
36       * Calls to this method should be balanced by calls to `restore`.
37       */
38      save() {
39          this._values.push(this._values[this._values.length - 1]);
40      }
41      /**
42       * Restore a previously saved value.
43       */
44      restore() {
45          if (this._values.length === 1) {
46              throw new RangeError("Calls to restore must balance previous calls to save");
47          }
48          this._values.pop();
49      }
50      // section Cloneable
51      clone() {
52          const copy = (0, clone_1.shallowCloneOf)(this);
53          copy._values = this._values.slice();
54          return copy;
55      }
56  }
57  exports.RewindableValue = RewindableValue;
58  //# sourceMappingURL=rewindable-value.js.map