tweak: Asynchronous refactoring

lib/findPaths.js

@@ -1,5 +1,5 @@
 /* Imports*/
-import React from "react";
+import React, { useState, useEffect } from 'react';
 import { toLocale, truncateValueForDisplay, numToAlphabeticalString, formatLargeOrSmall } from "../lib/utils.js"
 
 /* Utilities */
@@ -7,14 +7,13 @@ let avg = arr => arr.reduce((a, b) => (a + b), 0) / arr.length
 
 /* Main function */
 
-function findPathsInner({
+async function findPathsInner({
     sourceElementId, sourceElementPosition,
     targetElementId, targetElementPosition,
     links, nodes,
     maxLengthOfPath, pathSoFar
 }) {
     let paths = []
-    
     let minPos = Math.min(sourceElementPosition, targetElementPosition)
     let maxPos = Math.max(sourceElementPosition, targetElementPosition)
     let linksInner = links.filter(link => 
@@ -30,7 +29,7 @@ function findPathsInner({
             ) {
                 paths.push(pathSoFar.concat(link).flat())
             } else if ((link.source == sourceElementId)) {
-                let newPaths = findPathsInner({ 
+                let newPaths = await findPathsInner({ 
                     sourceElementId: link.target, sourceElementPosition: link.sourceElementPosition,
                     targetElementId, targetElementPosition,
                     pathSoFar: pathSoFar.concat(link).flat(), 
@@ -40,7 +39,7 @@ function findPathsInner({
                     paths.push(...newPaths)
                 }
             } else if ((link.target == sourceElementId)) {
-                let newPaths = findPathsInner({ 
+                let newPaths = await findPathsInner({ 
                     sourceElementId: link.source, sourceElementPosition: link.sourceElementPosition,
                     targetElementId, targetElementPosition,
                     pathSoFar: pathSoFar.concat(link).flat(), 
@@ -72,13 +71,13 @@ function findPaths({
 }
 */
 
-function findDistance({
+async function findDistance({
     sourceElementId, sourceElementPosition,
     targetElementId, targetElementPosition,
     nodes, links, direction
 }) {
     let maxLengthOfPath = Math.abs(sourceElementPosition - targetElementPosition)
-    let paths = findPathsInner({
+    let paths = await findPathsInner({
         sourceElementId, sourceElementPosition,
         targetElementId, targetElementPosition,
         links, nodes, direction,
@@ -112,36 +111,7 @@ function findDistance({
     //return weights.map(weight => Math.round(weight*100)/100)
 }
 
-function getDirectionalLinks({ nodes, links }) {
+async function findDistancesForAllElements({ nodes, links }) {
-    console.log("getDirectionalLinks")
-    // direction: 1 for upwards, -1 for downwards
-    let upwardsLinks = []
-    let downwardsLinks = []
-    links.forEach(link => {
-        console.log(link)
-        let sourceElementId = link.source
-        let targetElementId = link.target
-        if (link.distance < 1) {
-            // We already deal with this case upstream, but whatever.
-            [sourceElementId, targetElementId] = [targetElementId, sourceElementId]
-        }
-        let sourceElementPosition = nodes.find(element => element.id == sourceElementId).position
-        let targetElementPosition = nodes.find(element => element.id == targetElementId).position
-        if (link.distance == 1) {
-            // If two elements are the same, then they belong to both upwards and downwards paths!!
-            upwardsLinks.push(link)
-            downwardsLinks.push(link)
-        } else if (sourceElementPosition < targetElementPosition) {
-            upwardsLinks.push(link)
-        } else {
-            downwardsLinks.push(link)
-        }
-    })
-    console.log([upwardsLinks, downwardsLinks])
-    return [upwardsLinks, downwardsLinks]
-}
-
-function findDistancesForAllElements({ nodes, links }) {
     let referenceElements = nodes.filter(x => x.isReferenceValue)
     let midpoint = Math.round(nodes.length / 2)
     let referenceElement = referenceElements.length > 0 ? referenceElements[0] : nodes[midpoint]
@@ -166,6 +136,7 @@ function findDistancesForAllElements({ nodes, links }) {
             return distance
         }
     })
+    distances = await Promise.all(distances)
     return distances
 }
 
@@ -185,9 +156,13 @@ function abridgeArrayAndDisplay(array) {
 }
 
 export function CreateTableWithDistances({ isListOrdered, orderedList, listOfElements, links }) {
-    if (!isListOrdered || orderedList.length < listOfElements.length) {
+    const [rows, setRows] = useState([])
-        return (<div>{""}</div>)
+
-    } else {
+    useEffect(async () => {
+        // https://stackoverflow.com/questions/57847626/using-async-await-inside-a-react-functional-component
+        // https://stackoverflow.com/questions/54936559/using-async-await-in-react-component
+        // https://reactjs.org/docs/hooks-effect.html#tip-optimizing-performance-by-skipping-effects
+        if (isListOrdered && ! (orderedList.length < listOfElements.length) && rows.length == 0) {
             let nodes = []
             let positionDictionary=({})
             orderedList.forEach((id, pos) => {
@@ -200,11 +175,19 @@ export function CreateTableWithDistances({ isListOrdered, orderedList, listOfEle
                 sourceElementPosition: positionDictionary[link.source], 
                 targetElementPosition: positionDictionary[link.target]
             }))
-        /* Continue */
+    
-        let distances = findDistancesForAllElements({ nodes, links })
+            let distances = await findDistancesForAllElements({ nodes, links })
-        let rows = nodes.map((element, i) => ({ id: numToAlphabeticalString(element.position), position: element.position, name: element.name, distances: distances[i] }))
+            setRows(nodes.map((element, i) => ({ 
+                id: numToAlphabeticalString(element.position), 
+                position: element.position, 
+                name: element.name, 
+                distances: distances[i] 
+            })))
             console.log("rows@CreateTableWithDistances")
             console.log(rows)
+        }
+    }); // this useEffect should ideally only work when isListOrdered changes, but I haven't bothered to program that.
+
     return (
         <div>
             <table className="">
@@ -238,7 +221,6 @@ export function CreateTableWithDistances({ isListOrdered, orderedList, listOfEle
             </table>
         </div>
     )
-    }
 
 }