Function interpolate

docs/app/js/sanddance-app.js:127010–127013

(type, gamma)

    }
}
function interpolate(type, gamma) {
    const interp = _d3Interpolate[method(type)];
    return gamma != null && interp && interp.gamma ? interp.gamma(gamma) : interp;
}
function method(type) {
    return "interpolate" + type.toLowerCase().split("-").map((s)=>s[0].toUpperCase() + s.slice(1)).join("");
}