functional-data-structure/finger-tree

export function CachedMeasure(M) {
    this.M = M;
}

CachedMeasure.prototype.zero = function () {
    return this.M.zero();
};

CachedMeasure.prototype.plus = function (a, b) {
    return this.M.plus(a, b);
};

CachedMeasure.prototype.measure = function (measured) {
    return measured.measure();
};