clue solver – now in TypeScript!

Here’s a new version of my Clue solver! It works exactly the same as the old version, but now it uses a more standard React build system (so maybe it’s a little faster?) and I ported it to TypeScript.

TypeScript is now my favorite way to write React apps. It’s really nice to have a real type system with compile-time errors, and it gives me much more confidence when I refactor things.

For a comparison, here’s the old code in plain JavaScript, and here’s the new code in TypeScript. One representative sample of how much nicer things are, in the History class’s render method:

Old code:

for (var i = 0; i < this.props.history.length; ++i)
{
    var event = this.props.history[i][0];
    var eventType = event[0];
    var description = '';
    if (eventType === "suggestion") {
        description = this.props.playerInfo[event[1]][0] + " suggested " + CARD_NAMES[0][event[2]].external + ", " + CARD_NAMES[1][event[3]].external + ", " + CARD_NAMES[2][event[4]].external + " ";
        if (event[5] == -1) {
            description += " - no one refuted";
        }
        else {
            description += " - refuted by " + this.props.playerInfo[event[5]][0] + " with card ";
            if (event[6][0] == -1 && event[6][1] == -1) {
                description += "Unknown";
            }
            else {
                description += CARD_NAMES[event[6][0]][event[6][1]].external;
            }
        }
    } else if (eventType === "whoOwns") {
        var player = "Solution (case file)";
        if (event[1] < this.props.playerInfo.length) {
            player = this.props.playerInfo[event[1]][0];
        }
        description = CARD_NAMES[event[2][0]][event[2][1]].external + " owned by " + player;
    }
    entries.push(<li key={i}>{description}</li>);
}

New code:

let entries = [];
for (let i = 0; i < this.props.history.length; ++i)
{
    let event = this.props.history[i].event;
    let description = '';
    switch (event.history_type) {
        case "suggestion":
            description = this.props.playerInfos[event.suggester_index].name + " suggested " +
                cardNameFromCardIndex({ card_type: CardType.Suspects, index: event.suspect_index }).external + ", " +
                cardNameFromCardIndex({ card_type: CardType.Weapons, index: event.weapon_index }).external + ", " +
                cardNameFromCardIndex({ card_type: CardType.Rooms, index: event.room_index }).external + " ";
            if (event.refuter_index == -1) {
                description += " - no one refuted";
            }
            else {
                description += " - refuted by " + this.props.playerInfos[event.refuter_index].name + " with card ";
                if (isNull(event.refuted_card_index) || isNone(event.refuted_card_index)) {
                    description += "Unknown";
                }
                else {
                    description += cardNameFromCardIndex(event.refuted_card_index).external;
                }
            }
            break;
        case "whoOwns":
            let player = "Solution (case file)";
            if (event.player_index < this.props.playerInfos.length) {
                player = this.props.playerInfos[event.player_index].name;
            }
            description = cardNameFromCardIndex(event.card_index).external + " owned by " + player;
            break;
    }
    entries.push(<li key={i}>{description}</li>);
}

The new code is so much more readable! To be fair, some of the refactoring I could have done in JavaScript to begin with, but TypeScript gives me much more confidence to do bigger refactors.

Also, Visual Studio gives me Intellisense and the ability to rename variables and whatnot. I really don’t want to go back to writing JavaScript in a non-IDE!