rollup generates invalid code

[Mavrin]

rollup generates

bars.exit()
            .classed('tau-removing', true)
            .call(createUpdateFunc(config.guide.animationSpeed, null, (_a = {}, _a[barX] = function () {
                var d3This = d3.select(this);
                var x = d3This.attr(barX) - 0;
                var w = d3This.attr(barW) - 0;
                return x + w / 2;
            }, _a[barY] = function () {
                return this.getAttribute('data-zero');
            }, _a[barW] = 0, _a[barH] = 0, _a), 

but should

bars.exit()
            .classed('tau-removing', true)
            .call(createUpdateFunc(config.guide.animationSpeed, null, (_a = {}, _a[barX] = function () {
                var d3This = d3Selection.select(this);
                var x = d3This.attr(barX) - 0;
                var w = d3This.attr(barW) - 0;
                return x + w / 2;
            }, _a[barY] = function () {
                return this.getAttribute('data-zero');
            }, _a[barW] = 0, _a[barH] = 0, _a),