Clear an array in Polymer?

The polymer documentation says to always use the polymer array mutation functions when manipulating arrays. I do not see a function to clear an array. I see pop, push, shift, unshift and splice. For now i using this method:

<script>
    Polymer({
        is: "wc-example",
        properties: {
            data: { type: Array, value: function () { return [1, 2, 3]; } }
        },
        ready: function () {
            this.data = [];
        }
    });
</script>

This works but it doesn't seem right because i'm not using the array mutation functions. Does anyone know the correct solution?

Thank you!