function update$6(op, value, options) {
    const opt = options || NO_OPT;
    if (op.set(value) || opt.force) {
      this.touch(op, opt);
    }
    return this;
  }
Updates the value of the given operator.
@param {Operator} op - The operator to update.
@param {*} value - The value to set.
@param {object} [options] - Additional options hash.
@param {boolean} [options.force] - If true, the operator will
  be re-evaluated even if its value has not changed.
@param {boolean} [options.skip] - If true, the operator will
  be skipped: it will not be evaluated, but its dependents will be.
@return {Dataflow}