Function main

javascript_games/snailrace.js:20–101

()

async function main() {
    console.log('Snail Race, by Al Sweigart al@inventwithpython.com\n\n    @v <-- snail\n\n');

    // Ask how many snails to race:
    while (true) {
        console.log('How many snails will race? Max:', MAX_NUM_SNAILS);
        let response = readlineSync.question('> ');
        if (!isNaN(response)) {
            var numSnailsRacing = Number(response);
            if (1 < numSnailsRacing <= MAX_NUM_SNAILS) {
                break;
            }
        }
        console.log('Enter a number between 2 and', MAX_NUM_SNAILS);
    }

    // Enter the names of each snail:
    let snailNames = [];  // Array of the string snail names.
    for (let i = 1; i <= numSnailsRacing; i++) {
        while (true) {  // Keep asking until the player enters a valid name.
            console.log('Enter snail #' + i.toString() + "'s name:");
            var name = readlineSync.question('> ');
            if (name.length === 0) {
                console.log('Please enter a name.');
            } else if (snailNames.includes(name)) {
                console.log('Choose a name that has not already been used.');
            } else {
                break;  // The entered name is acceptable.
            }
        }
        snailNames.push(name);
    }

    // Display each snail at the start line.
    console.log('\n'.repeat(40));
    console.log('START' + ' '.repeat(FINISH_LINE - 'START'.length) + 'FINISH');
    console.log('|' + (' '.repeat(FINISH_LINE - '|'.length)) + '|');
    let snailProgress = {};
    for (let i = 0; i < snailNames.length; i++) {
        let snailName = snailNames[i];
        console.log(snailName.substr(0, MAX_NAME_LENGTH));
        console.log('@v');
        snailProgress[snailName] = 0;
    }

    await sleep(1.5);  // The pause right before the race starts.

    while (true) {  // Main program loop.
        // Pick random snails to move forward:
        let numSnailsToMove = Math.floor(Math.random() * Math.floor(numSnailsRacing / 2)) + 1;
        for (let i = 0; i < numSnailsToMove; i++) {
            let randomSnailName = snailNames[Math.floor(Math.random() * snailNames.length)];
            snailProgress[randomSnailName] += 1;

            // Check if a snail has reached the finish line:
            if (snailProgress[randomSnailName] == FINISH_LINE) {
                console.log(randomSnailName, 'has won!');
                return;