Run results for: RXJS vs Vanilla

Run details:

User agent: Mozilla/5.0 (Linux; Android 8.0.0; LG-H872) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.181 Mobile Safari/537.36

Browser: Chrome Mobile 88

Operating system: Android 8.0.0

Device Platform: Mobile

Date tested: 3 years ago

Test name	Executions per second
RXJS	7621.5 Ops/sec
Vanilla	21004.1 Ops/sec

HTML Preparation code:

<script src="https://d3js.org/d3.v5.min.js"></script>
<script src='https://unpkg.com/rxjs@6.5.5/bundles/rxjs.umd.min.js'></script>

Script Preparation code:

var rawdata = [{"rect":{"y":80.39215686274508,"width":79.10307898259705,"height":17.64705882352941},"value":5909,"label":{"value":"2020-01-27 15:52:39.000","x":39.55153949129853,"y":89.21568627450979}},{"rect":{"y":60.784313725490186,"width":104.99330655957162,"height":17.64705882352941},"value":7843,"label":{"value":"2019-11-11 20:55:13.000","x":52.49665327978581,"y":69.60784313725489}},{"rect":{"y":41.17647058823529,"width":107.1619812583668,"height":17.64705882352941},"value":8005,"label":{"value":"2020-04-14 18:29:52.000","x":53.5809906291834,"y":49.99999999999999}},{"rect":{"y":21.56862745098039,"width":137.46987951807228,"height":17.64705882352941},"value":10269,"label":{"value":"2020-01-22 15:48:25.000","x":68.73493975903614,"y":30.392156862745097}},{"rect":{"y":1.9607843137254903,"width":270,"height":17.64705882352941},"value":20169,"label":{"value":"2020-01-03 19:09:13.000","x":135,"y":10.784313725490195}}];
var x = d3.scaleLinear().range([0, 300]);
var y = d3.scaleBand().range([250, 0]).padding(0.1);

Tests:

RXJS
let { from, Observable } = rxjs; let { flatMap, map, tap, toArray } = rxjs.operators; var data$ = from(rawdata) .pipe( toArray(), map(values => values.sort((a, b) => b.value - a.value)), map(values => values.reverse()), map(values => values.slice(0, 5)), tap((values) => { x = x.domain([0, d3.max(values, d => d.value)]); y = y.domain(values.map((d) => d.label)); }), flatMap(values => values), map(bar => ({ rect: { y: y(bar.label), width: x(bar.value), height: y.bandwidth() }, value: bar.value, label: { value: bar.label, x: x(bar.value) <= 300 / 5 ? x(bar.value) + 10 : x(bar.value) / 2, y: y(bar.label) + y.bandwidth() / 2 } })), toArray() ); let data; data$.subscribe(d => data = d);
Vanilla
let values = rawdata.sort((a, b) => a.value - b.value).slice(0, 5); // Set x and y values x = x.domain([0, d3.max(values, d => d.value)]); y = y.domain(values.map((d) => d.label)); // Set bars on chartmap var data = values.map(bar => ({ rect: { y: y(bar.label), width: x(bar.value), height: y.bandwidth() }, value: bar.value.toString(), label: { value: bar.label, x: x(bar.value) <= 300 / 5 ? x(bar.value) + 10 : x(bar.value) / 2, y: y(bar.label) + y.bandwidth() / 2 } }))