From fffb5ca1e9f0caa431ef6be1bf81ca3c9281662c Mon Sep 17 00:00:00 2001
From: Julius Volz <julius.volz@gmail.com>
Date: Sat, 2 Nov 2019 21:45:22 +0100
Subject: [PATCH] React UI: More conversions to Function Components (#6259)

* React UI: More conversions to Function Components

Signed-off-by: Julius Volz <julius.volz@gmail.com>

* Address chat feedback over Riot

Signed-off-by: Julius Volz <julius.volz@gmail.com>
---
 web/ui/react-app/src/DataTable.tsx  | 154 ++++++++++++++--------------
 web/ui/react-app/src/Legend.tsx     |  46 ++++-----
 web/ui/react-app/src/SeriesName.tsx |  39 +++----
 3 files changed, 109 insertions(+), 130 deletions(-)

diff --git a/web/ui/react-app/src/DataTable.tsx b/web/ui/react-app/src/DataTable.tsx
index 9f1a52ceb..877a60228 100644
--- a/web/ui/react-app/src/DataTable.tsx
+++ b/web/ui/react-app/src/DataTable.tsx
@@ -1,4 +1,4 @@
-import React, { PureComponent, ReactNode } from 'react';
+import React, { FC, ReactNode } from 'react';
 
 import { Alert, Table } from 'reactstrap';
 
@@ -41,96 +41,92 @@ interface Metric {
 
 type SampleValue = [number, string];
 
-class DataTable extends PureComponent<QueryResult> {
-  limitSeries(series: InstantSample[] | RangeSamples[]): InstantSample[] | RangeSamples[] {
-    const maxSeries = 10000;
+const limitSeries = <S extends InstantSample | RangeSamples>(series: S[]): S[] => {
+  const maxSeries = 10000;
 
-    if (series.length > maxSeries) {
-      return series.slice(0, maxSeries);
-    }
-    return series;
+  if (series.length > maxSeries) {
+    return series.slice(0, maxSeries);
+  }
+  return series;
+};
+
+const DataTable: FC<QueryResult> = ({ data }) => {
+  if (data === null) {
+    return <Alert color="light">No data queried yet</Alert>;
   }
 
-  render() {
-    const data = this.props.data;
+  if (data.result === null || data.result.length === 0) {
+    return <Alert color="secondary">Empty query result</Alert>;
+  }
 
-    if (data === null) {
-      return <Alert color="light">No data queried yet</Alert>;
-    }
-
-    if (data.result === null || data.result.length === 0) {
-      return <Alert color="secondary">Empty query result</Alert>;
-    }
-
-    let rows: ReactNode[] = [];
-    let limited = false;
-    switch (data.resultType) {
-      case 'vector':
-        rows = (this.limitSeries(data.result) as InstantSample[]).map(
-          (s: InstantSample, index: number): ReactNode => {
-            return (
-              <tr key={index}>
-                <td>
-                  <SeriesName labels={s.metric} format={false} />
-                </td>
-                <td>{s.value[1]}</td>
-              </tr>
-            );
-          }
-        );
-        limited = rows.length !== data.result.length;
-        break;
-      case 'matrix':
-        rows = (this.limitSeries(data.result) as RangeSamples[]).map((s, index) => {
-          const valueText = s.values
-            .map(v => {
-              return [1] + ' @' + v[0];
-            })
-            .join('\n');
+  let rows: ReactNode[] = [];
+  let limited = false;
+  switch (data.resultType) {
+    case 'vector':
+      rows = (limitSeries(data.result) as InstantSample[]).map(
+        (s: InstantSample, index: number): ReactNode => {
           return (
-            <tr style={{ whiteSpace: 'pre' }} key={index}>
+            <tr key={index}>
               <td>
                 <SeriesName labels={s.metric} format={false} />
               </td>
-              <td>{valueText}</td>
+              <td>{s.value[1]}</td>
             </tr>
           );
-        });
-        limited = rows.length !== data.result.length;
-        break;
-      case 'scalar':
-        rows.push(
-          <tr key="0">
-            <td>scalar</td>
-            <td>{data.result[1]}</td>
+        }
+      );
+      limited = rows.length !== data.result.length;
+      break;
+    case 'matrix':
+      rows = (limitSeries(data.result) as RangeSamples[]).map((s, index) => {
+        const valueText = s.values
+          .map(v => {
+            return [1] + ' @' + v[0];
+          })
+          .join('\n');
+        return (
+          <tr style={{ whiteSpace: 'pre' }} key={index}>
+            <td>
+              <SeriesName labels={s.metric} format={false} />
+            </td>
+            <td>{valueText}</td>
           </tr>
         );
-        break;
-      case 'string':
-        rows.push(
-          <tr key="0">
-            <td>scalar</td>
-            <td>{data.result[1]}</td>
-          </tr>
-        );
-        break;
-      default:
-        return <Alert color="danger">Unsupported result value type</Alert>;
-    }
-
-    return (
-      <>
-        {limited && (
-          <Alert color="danger">
-            <strong>Warning:</strong> Fetched {data.result.length} metrics, only displaying first {rows.length}.
-          </Alert>
-        )}
-        <Table hover size="sm" className="data-table">
-          <tbody>{rows}</tbody>
-        </Table>
-      </>
-    );
+      });
+      limited = rows.length !== data.result.length;
+      break;
+    case 'scalar':
+      rows.push(
+        <tr key="0">
+          <td>scalar</td>
+          <td>{data.result[1]}</td>
+        </tr>
+      );
+      break;
+    case 'string':
+      rows.push(
+        <tr key="0">
+          <td>scalar</td>
+          <td>{data.result[1]}</td>
+        </tr>
+      );
+      break;
+    default:
+      return <Alert color="danger">Unsupported result value type</Alert>;
   }
-}
+
+  return (
+    <>
+      {limited && (
+        <Alert color="danger">
+          <strong>Warning:</strong> Fetched {data.result.length} metrics, only displaying first {rows.length}.
+        </Alert>
+      )}
+      <Table hover size="sm" className="data-table">
+        <tbody>{rows}</tbody>
+      </Table>
+    </>
+  );
+};
 
 export default DataTable;
diff --git a/web/ui/react-app/src/Legend.tsx b/web/ui/react-app/src/Legend.tsx
index 88cd2c4a0..b0f60c9e1 100644
--- a/web/ui/react-app/src/Legend.tsx
+++ b/web/ui/react-app/src/Legend.tsx
@@ -1,4 +1,4 @@
-import React, { PureComponent } from 'react';
+import React, { FC } from 'react';
 
 import SeriesName from './SeriesName';
 
@@ -6,31 +6,23 @@ interface LegendProps {
   series: any; // TODO: Type this.
 }
 
-class Legend extends PureComponent<LegendProps> {
-  renderLegendItem(s: any) {
-    return (
-      <tr key={s.index} className="legend-item">
-        <td>
-          <div className="legend-swatch" style={{ backgroundColor: s.color }}></div>
-        </td>
-        <td>
-          <SeriesName labels={s.labels} format={true} />
-        </td>
-      </tr>
-    );
-  }
-
-  render() {
-    return (
-      <table className="graph-legend">
-        <tbody>
-          {this.props.series.map((s: any) => {
-            return this.renderLegendItem(s);
-          })}
-        </tbody>
-      </table>
-    );
-  }
-}
+const Legend: FC<LegendProps> = ({ series }) => {
+  return (
+    <table className="graph-legend">
+      <tbody>
+        {series.map((s: any) => (
+          <tr key={s.index} className="legend-item">
+            <td>
+              <div className="legend-swatch" style={{ backgroundColor: s.color }}></div>
+            </td>
+            <td>
+              <SeriesName labels={s.labels} format={true} />
+            </td>
+          </tr>
+        ))}
+      </tbody>
+    </table>
+  );
+};
 
 export default Legend;
diff --git a/web/ui/react-app/src/SeriesName.tsx b/web/ui/react-app/src/SeriesName.tsx
index edbe1d97d..370a8dfef 100644
--- a/web/ui/react-app/src/SeriesName.tsx
+++ b/web/ui/react-app/src/SeriesName.tsx
@@ -1,4 +1,4 @@
-import React, { PureComponent } from 'react';
+import React, { FC } from 'react';
 import metricToSeriesName from './MetricFormat';
 
 interface SeriesNameProps {
@@ -6,11 +6,9 @@ interface SeriesNameProps {
   format: boolean;
 }
 
-class SeriesName extends PureComponent<SeriesNameProps> {
-  renderFormatted(): React.ReactNode {
-    const labels = this.props.labels!;
-
-    const labelNodes: React.ReactNode[] = [];
+const SeriesName: FC<SeriesNameProps> = ({ labels, format }) => {
+  const renderFormatted = (): React.ReactElement => {
+    const labelNodes: React.ReactElement[] = [];
     let first = true;
     for (const label in labels) {
       if (label === '__name__') {
@@ -31,31 +29,24 @@ class SeriesName extends PureComponent<SeriesNameProps> {
 
     return (
       <>
-        <span className="legend-metric-name">{labels.__name__ || ''}</span>
+        <span className="legend-metric-name">{labels!.__name__ || ''}</span>
         <span className="legend-label-brace">{'{'}</span>
         {labelNodes}
         <span className="legend-label-brace">{'}'}</span>
       </>
     );
+  };
+
+  if (labels === null) {
+    return <>scalar</>;
   }
 
-  renderPlain() {
-    const labels = this.props.labels!;
-    return metricToSeriesName(labels);
+  if (format) {
+    return renderFormatted();
   }
-
-  render() {
-    if (this.props.labels === null) {
-      return 'scalar';
-    }
-
-    if (this.props.format) {
-      return this.renderFormatted();
-    }
-    // Return a simple text node. This is much faster to scroll through
-    // for longer lists (hundreds of items).
-    return this.renderPlain();
-  }
-}
+  // Return a simple text node. This is much faster to scroll through
+  // for longer lists (hundreds of items).
+  return <>{metricToSeriesName(labels!)}</>;
+};
 
 export default SeriesName;