| 100 | * @returns {void} |
| 101 | */ |
| 102 | export function previous (engine: VisualNovelEngine): Promise<void> { |
| 103 | return new Promise<void> ((resolve) => { |
| 104 | setTimeout (() => { |
| 105 | engine.revert ().then (() => { |
| 106 | engine.global ('_engine_block', false); |
| 107 | resolve (); |
| 108 | }).catch ((e) => { |
| 109 | engine.debug.log ('Revert was prevented.\n', e); |
| 110 | engine.global ('_engine_block', false); |
| 111 | |
| 112 | // The game could not be reverted, either because an |
| 113 | // action prevented it or because there are no statements |
| 114 | // left to revert to. |
| 115 | const currentStep = engine.state ('step') as number; |
| 116 | |
| 117 | if (currentStep > 0) { |
| 118 | engine.state ({ |
| 119 | step: currentStep - 1 |
| 120 | }); |
| 121 | } |
| 122 | |
| 123 | engine.proceed ({ userInitiated: false, skip: false, autoPlay: false }).then (() => { |
| 124 | resolve (); |
| 125 | }); |
| 126 | }); |
| 127 | }, 0); |
| 128 | }); |
| 129 | } |
| 130 | |
| 131 | // ============================================================================ |
| 132 | // Action Preparation |