easingMap: Readonly<Map<
    | "sine-in"
    | "sine-out"
    | "sine-in-out"
    | "power1-in"
    | "power1-out"
    | "power1-in-out"
    | "power2-in"
    | "power2-out"
    | "power2-in-out"
    | "power3-in"
    | "power3-out"
    | "power3-in-out"
    | "power4-in"
    | "power4-out"
    | "power4-in-out"
    | "quad-in"
    | "quad-out"
    | "quad-in-out"
    | "expo-in"
    | "expo-out"
    | "expo-in-out"
    | "circ-in"
    | "circ-out"
    | "circ-in-out"
    | "back-in"
    | "back-out"
    | "back-in-out"
    | "elastic-in"
    | "elastic-out"
    | "elastic-in-out"
    | "bounce-in"
    | "bounce-out"
    | "bounce-in-out", string>> = ...

Map mapping custom preset easing strings to linear easing functions. Keys are one-to-one with PresetLinearEasingKey.