pcottle/learnGitBranching · info · CommandResult

getHint()

Error message

getHint()

What it means

Thrown when a user types `hint` while a level is active. The `getHint()` helper in level/index.js raises a CommandResult error whose message is the current level's next solution step (from its solution chain). This is the app's interactive 'give me a hint' mechanism — the throw is how the command pipeline surfaces text to the UI, not a real failure.

Source

Thrown at src/js/level/index.js:624

  }

  getInstantCommands() {
    var getHint = function() {
      var hint = intl.getHint(this.level);
      if (!hint || !hint.length) {
        return intl.str('no-hint');
      }
      return hint;
    }.bind(this);

    return [
      [/^help$|^\?$/, function() {
        throw new Errors.CommandResult({
          msg: intl.str('help-vague-level')
        });
      }],
      [/^hint$/, function() {
        throw new Errors.CommandResult({
          msg: getHint()
        });
      }]
    ];
  }

  reset(command, deferred) {
    this.gitCommandsIssued = [];

    var commandStr = (command) ? command.get('rawStr') : '';
    if (!this.testOptionOnString(commandStr, 'forSolution')) {
      this.isShowingSolution = false;
    }
    if (this.solved) {
      this.wasResetAfterSolved = true;
    }
    this.solved = false;
    super.reset(command, deferred);

View on GitHub (pinned to 5b09d0ff96)

Solutions

  1. Ensure a level is actually loaded before dispatching `hint` (check the level store state)
  2. When authoring custom levels, always define a solution array so the hint chain has steps to reveal
  3. In tests, load or mock a level before exercising the hint instant command
  4. In free-play mode, catch CommandResult and show a friendly 'no hints outside levels' message
Defensive patterns

Strategy: try-catch

Validate before calling

const level = levelStore.getCurrentLevel ? levelStore.getCurrentLevel() : null;
if (!level || !level.solution) { /* don't dispatch `hint` */ }

Type guard

function hasHint(level) {
  return !!(level && level.solution && level.solution.length);
}

Try / catch

try {
  dispatch('hint');
} catch (e) {
  if (e instanceof Errors.CommandResult) { showMsg(e.msg); } else { throw e; }
}

Prevention

When it happens

Trigger: Typing `hint` (matched by /^hint$/) in the command line while a level is loaded and initParseWaterfall dispatches the instant command. If the level has no hint/solution defined, getHint() itself may fail or return empty.

Common situations: Custom levels authored without a `solution` or hint chain; calling `hint` in sandbox/free-play mode where no level (and hence no hint) exists; tests that dispatch instant commands without loading a level first.

Related errors

AI-assisted analysis of pcottle/learnGitBranching@5b09d0ff96 (2026-08-27). Data as JSON: /api/errors/48e91ab189dc6211. Report an issue: GitHub.