Prevent unnecessary re-renders

src/components/Calculator.tsx

@@ -1,4 +1,4 @@
-import React, { useState, useCallback, useEffect } from 'react'
+import React from 'react'
 import { Map } from 'immutable'
 import { TalentTree } from './TalentTree'
 import { 
@@ -12,48 +12,56 @@ interface Props {
   selectedClass: string
 }
 
-const initMap = Map<number, number>()
+const EMPTY_TALENTS = Map<number, number>()
 
-// TODO: Wrap in "IndexRoute" or something similar to take care of the url params
-//       Calculator doesn't need to know about URL params
+export class Calculator extends React.PureComponent<Props> {
+  static whyDidYouRender = true
 
-export const Calculator: React.FC<Props> = ({ selectedClass }) => {
-  const [knownTalents, setKnownTalents] = useState(initMap)
+  state = {
+    knownTalents: EMPTY_TALENTS
+  }
 
-  const handleTalentPress = useCallback((specId: number, talentId: number, modifier: 1 | -1) => {
+  componentDidUpdate(prevProps: Props) {
+    if (prevProps.selectedClass !== this.props.selectedClass) {
+      this.setState({ 
+        knownTalents: EMPTY_TALENTS 
+      })
+    }
+  }
+  
+  handleTalentPress = (specId: number, talentId: number, modifier: 1 | -1) => {
     const talent = talentsBySpec[specId][talentId]
-    setKnownTalents(knownTalents =>
-      modifyTalentPoint(knownTalents, talent, modifier)
+    this.setState({ 
+      knownTalents: modifyTalentPoint(this.state.knownTalents, talent, modifier)
+    })
+  }
+
+  render() {
+    const { selectedClass } = this.props
+    const { knownTalents } = this.state
+
+    const classData = classByName[selectedClass]
+    const availablePoints = calcAvailablePoints(knownTalents)
+
+    return (
+      <div className="calculator">
+        <div className="trees">
+          {classData.specs.map((specId) => (
+            <TalentTree
+              key={specId}
+              specId={specId}
+              availablePoints={availablePoints}
+              knownTalents={knownTalents}
+              onTalentPress={this.handleTalentPress}
+            />
+          ))}
+        </div>
+
+        <div className="calculator__points">
+          Points: {availablePoints}
+        </div>
+      </div>
     )
-  }, [])
-
-  // Reset known talents when switching class
-  useEffect(() => {
-    setKnownTalents(initMap)
-  }, [selectedClass])
-
-  const classData = classByName[selectedClass]
-  const availablePoints = calcAvailablePoints(knownTalents)
-
-  return (
-    <div className="calculator">
-      <div className="trees">
-        {classData.specs.map((specId) => (
-          <TalentTree
-            key={specId}
-            specId={specId}
-            availablePoints={availablePoints}
-            knownTalents={knownTalents}
-            onTalentPress={handleTalentPress}
-          />
-        ))}
-      </div>
-
-      <div className="calculator__points">
-        Points: {availablePoints}
-      </div>
-    </div>
-  )
+  }
 }
 
-(Calculator as any).whyDidYouRender = true

src/components/ClassPicker.tsx

@@ -1,12 +1,18 @@
 import React from 'react'
+import { NavLink } from 'react-router-dom'
+import { classByName } from '../data/classes'
 
 interface Props {
 }
 
 export const ClassPicker: React.FC<Props> = () => {
   return (
-    <div className="">
-      Pick your class
-    </div>
+    <ul className="class-picker">
+      {Object.values(classByName).map((c) => 
+        <li key={c.id} className="class-picker__class">
+          <NavLink to={`/${c.name.toLowerCase()}`}>{c.name}</NavLink>
+        </li>
+      )}
+    </ul>
   )
 }

src/components/IndexRoute.tsx

@@ -1,6 +1,6 @@
 import React from 'react'
 import { Calculator } from './Calculator'
-import { Link } from 'react-router-dom';
+import { ClassPicker } from './ClassPicker'
 
 interface Props {
   pointString?: string // e.g. 2305302300--001
@@ -8,28 +8,28 @@ interface Props {
   history: any
 }
 
-const ClassPicker = () => {
-  return <ul>
-    <li><Link to="/warlock">Warlock</Link></li>
-    <li><Link to="/paladin">Paladin</Link></li>
-  </ul>
-}
+export class IndexRoute extends React.PureComponent<Props> {
+  static whyDidYouRender = true
 
-export const IndexRoute: React.FC<Props> = ({ match, history }) => {
-  const { selectedClass, pointString } = match.params
+  render() {
+    const { match, history } = this.props
+    const { selectedClass, pointString } = match.params
   
-  if (!selectedClass) {
-    history.replace('/warlock')
-    return null
+    if (!selectedClass) {
+      history.replace('/warlock')
+      return null
+    }
+  
+    return (
+      <div className="index">
+        <ClassPicker />
+  
+        {selectedClass && 
+          <Calculator 
+            selectedClass={selectedClass}
+          />
+        }
+      </div>
+    )
   }
-
-  return (
-    <div className="index">
-      <ClassPicker />
-
-      {selectedClass && 
-        <Calculator selectedClass={selectedClass} />
-      }
-    </div>
-  )
 }

src/components/TalentSlot.scss

@@ -1,3 +1,8 @@
+$row-distance: 70px;
+
+@mixin rowStyle($rowNr) {
+  top: 30px + (($rowNr) * 70px);
+}
 
 .talent {
   position: absolute;
@@ -33,18 +38,15 @@
 
   }
 
-  $row-distance: 70px;
+  @for $i from 0 through 6 {
+    &[data-row="#{$i}"] {
+      @include rowStyle($i)
+    }
+  }
 
-  &[data-row="0"] { top: $row-distance; }
-  &[data-row="1"] { top: $row-distance * 2; }
-  &[data-row="2"] { top: $row-distance * 3; }
-  &[data-row="3"] { top: $row-distance * 4; }
-  &[data-row="4"] { top: $row-distance * 5; }
-  &[data-row="5"] { top: $row-distance * 6; }
-  &[data-row="6"] { top: $row-distance * 7; }
 
-  $col-distance-offset: 30px;
-  $col-distance: 50px;
+  $col-distance-offset: 44px;
+  $col-distance: 56px;
 
   &[data-col="0"] { left: $col-distance-offset; }
   &[data-col="1"] { left: $col-distance-offset + ($col-distance * 1); }

src/components/TalentSlot.tsx

@@ -2,7 +2,6 @@ import './TalentSlot.scss'
 import React, { FC } from 'react'
 import { Icon } from './Icon'
 import classNames from 'classnames'
-import { spells } from '../data/spells'
 import { Map } from 'immutable';
 import { getPointsInSpec, calcMeetsRequirements } from '../lib/tree';
 
@@ -14,8 +13,13 @@ interface Props {
   knownTalents: Map<number, number>
   /** Disabled override */
   disabled?: boolean
-  onClick?: (e: any) => void
-  onRightClick?: (e: any) => void
+  onClick?: (talentId: number) => void
+  onRightClick?: (talentId: number) => void
+}
+
+const defaultProps: Partial<Props> = {
+  onClick: () => undefined,
+  onRightClick: () => undefined
 }
 
 const isAvailable = (talent: TalentData, specId: number, knownTalents: Map<number, number>): boolean => {
@@ -39,7 +43,7 @@ export const TalentSlot: FC<Props> = (props) => {
   })
 
   const handleContextMenu = (e) => {
-    if (props.onRightClick) props.onRightClick(e)
+    if (props.onRightClick) props.onRightClick(talent.id)
     e.preventDefault()
     return false
   }
@@ -50,7 +54,7 @@ export const TalentSlot: FC<Props> = (props) => {
       title={talent.ranks[0].toString()}
       data-row={talent.row}
       data-col={talent.col}
-      onClick={!disabled ? props.onClick : () => {}}
+      onClick={!disabled ? () => props.onClick(talent.id) : () => {}}
       onContextMenu={handleContextMenu}
     >
       <Icon name={talent.icon} />
@@ -62,4 +66,6 @@ export const TalentSlot: FC<Props> = (props) => {
   )
 }
 
-(TalentSlot as any).whyDidYouRender = true
+TalentSlot.defaultProps = defaultProps
+
+// ;(TalentSlot as any).whyDidYouRender = true

src/components/TalentTree.tsx

@@ -1,4 +1,4 @@
-import React, { MouseEvent, useCallback } from 'react'
+import React, { useCallback } from 'react'
 import { Map }  from 'immutable'
 import { TalentSlot } from './TalentSlot';
 import { getPointsInSpec } from '../lib/tree';
@@ -14,32 +14,40 @@ interface Props {
 export const TalentTree: React.FC<Props> = ({ specId, knownTalents, availablePoints, onTalentPress }) => {
   const talents = Object.values(talentsBySpec[specId])
 
-  const handleTalentPress = useCallback((talentId: number, modifier: 1 | -1) => {
-    return (e: MouseEvent) => {
-      onTalentPress(specId, talentId, modifier)
-    }
-  }, [specId, onTalentPress])
+  const handleClick = useCallback(
+    (talentId) => onTalentPress(specId, talentId, 1), 
+    [specId, onTalentPress]
+  )
+  const handleRightClick = useCallback(
+    (talentId) => onTalentPress(specId, talentId, -1), 
+    [specId, onTalentPress]
+  )
 
-  const style = { 
+  const bodyStyle = { 
     backgroundImage: `url("https://wow.zamimg.com/images/wow/talents/backgrounds/classic/${specId}.jpg")`
   }
 
   return (
-    <div className="tree" style={style}>
-      <h2>{specNames[specId]} ({getPointsInSpec(specId, knownTalents)})</h2>
-      {talents.map((talent, index) => 
-        <TalentSlot 
-          key={talent.id}
-          specId={specId}
-          talent={talent}
-          availablePoints={availablePoints}
-          knownTalents={knownTalents}
-          onClick={handleTalentPress(talent.id, 1)}
-          onRightClick={handleTalentPress(talent.id, -1)}
-        />
-      )}
+    <div className="tree">
+      <div className="tree__header">
+        <h3>{specNames[specId]} ({getPointsInSpec(specId, knownTalents)})</h3>
+      </div>
+
+      <div className="tree__body" style={bodyStyle}>
+        {talents.map((talent) => 
+          <TalentSlot 
+            key={talent.id}
+            specId={specId}
+            talent={talent}
+            availablePoints={availablePoints}
+            knownTalents={knownTalents}
+            onClick={handleClick}
+            onRightClick={handleRightClick}
+          />
+        )}
+      </div>
     </div>
   )
 }
 
-(TalentTree as any).whyDidYouRender = true
+;(TalentTree as any).whyDidYouRender = true