howitworks-tuple-2.js

miniFc.tuple = (...itemGenerators) => {
    return {
        generate(mrng) {
            return itemGenerators.map(g => g.generate(mrng));
        },
        *shrink(value) {
            for (let index = 0 ; index !== itemGenerators.length ; ++index) {
                const currentGenerator = itemGenerators[index];
                const currentValue = value[index];
                for (const shrunkValue of currentGenerator.shrink(currentValue)) {
                    yield [...value.slice(0, index), shrunkValue, ...value.slice(index + 1)];
                }
            }
        }
    }
}
// You can check the output by calling:
// > [...miniFc.tuple(miniFc.integer(0, 100), miniFc.integer(0, 100), miniFc.integer(0, 100)).shrink([4, 3, 4])]