這篇文章主要介紹了基於javascript實現獲取最短路徑演算法程式碼例項,文中通過示例程式碼介紹的非常詳細，對大家的學習或者工作具有一定的參考學習價值,需要的朋友可以參考下

程式碼如下

//A演算法 自動尋路 路徑
class GetAutoPath{

 constructor(id,map,sPos,ePos,mapArr){
  //this.type = id.type;
  this.id = id;
  this.map = map;
  this.sPos = sPos;
  this.ePos = ePos;
  this.mapArr = mapArr;
  this.maxMach = 10000;
  this.openArr = [];
  this.closeArr = [];
  this.minPath = [];
  if(!this.isPath(this.sPos.x,this.sPos.y)){this.sPos = this.getNewDot(sPos,ePos);}
  if(!this.isPath(this.ePos.x,this.ePos.y)){this.ePos = this.getNewDot(ePos,sPos);}
  //console.log(this.mapArr);
  return this.run();
 }
 
 posts(txt,arr){//post訊息
  //let id = this.id,sPos = this.sPos,ePos = this.ePos,arrs = arr || [];
  return {id:this.id,map:this.map,arr:arr || [],sPos:this.sPos,ePos:this.ePos,txt:txt}
 }
 
 isPath(x,y){//isPath = true 合法路徑 = isBanPath === undefined
  let isPath = false,ym = this.mapArr.get(y),xm; //console.log(ym); debugger;
  if(ym !== undefined){
   xm = ym.get(x);
   if(xm !== undefined){
    if(xm.isBanPath === undefined){isPath = true;}
   }
  }
  //if(this.mapArr[y] !== undefined && this.mapArr[y][x] !== undefined && this.mapArr[y][x].isPath === 1){isPath = true;}
  return isPath;
 }
 
 getEqual(arr,x,y){//獲取目標陣列相同的座標
  let isPos = false;
  if(arr.length === 0){
   isPos = false;
  }else{
   isPos = arr.some(function (o){return o.x === x && o.y === y;});
  }
  return isPos;
 }

 getDot(x,y){//獲取周圍8個方向座標
  return [{x:x-1,y:y},{x:x+1,{x:x,y:y-1},y:y+1},{x:x-1,y:y+1}]
 } 
 
 getNewDot(setPos,pos){//重定義起點或終點
  let dot = setPos,pointDot,k,arr = [],arrs = [],g,end,maxMachT = 0;
  while(!end && maxMachT < this.maxMach){
   maxMachT++;
   pointDot = this.getDot(dot.x,dot.y);
   for(k in pointDot){
    g = Math.round(Math.sqrt(Math.abs(pointDot[k].x - pos.x) + Math.abs(pointDot[k].y - pos.y)) * 100) / 100;
    if(!this.isPath(pointDot[k].x,pointDot[k].y)){//不合法
     arr.push({x:pointDot[k].x,y:pointDot[k].y,g:g});
     arr.sort(function(a,b){return a.g - b.g;});
    }else{//合法
     arrs.push({x:pointDot[k].x,g:g});
     arrs.sort(function(a,b){return a.g - b.g;});
    }
    if(arrs.length > 0){end = true;}
   }
   dot = {x:arr[0].x,y:arr[0].y,g:arr[0].g}; arr = []; 
  }
  if(!arrs[0].x || !arrs[0].y){return this.posts("沒有符合的座標");}
  return {x:arrs[0].x,y:arrs[0].y};
 }
 
 run(){
  if(this.sPos.x === undefined || this.ePos.x === undefined){return this.posts("沒有符合的座標");}
  let sPos = this.sPos,point,key,i,newPoint,ger,gers,h,f,maxMachT = 0;
  this.openArr[0] = {x : sPos.x,y : sPos.y,f : 0,p : 0,ger : 0}
  while(this.openArr.length > 0){
   maxMachT++;
   point = this.openArr[0]; this.closeArr.push(point); this.openArr.splice(0,1);
   key = this.closeArr.length - 1;//設定當前節點
   newPoint = this.getDot(point.x,point.y);//獲取周圍點
   for(i in newPoint){//設定周圍點
    ger = Math.round(Math.sqrt(Math.abs(newPoint[i].x - point.x) + Math.abs(newPoint[i].y - point.y)) * 100) / 100;//到當前節點的曼哈頓距離,保留兩位小數點
    gers = ger + point.ger;
    g = Math.round(gers * 100) / 100;
    h = Math.abs(newPoint[i].x - ePos.x) + Math.abs(newPoint[i].y - ePos.y);
    f = g + h;
    if(this.isPath(newPoint[i].x,newPoint[i].y) && !this.getEqual(this.openArr,newPoint[i].x,newPoint[i].y) && !this.getEqual(this.closeArr,newPoint[i].y)){this.openArr.push({x:newPoint[i].x,y:newPoint[i].y,f:f,p:key,ger:ger});}
   }
   this.openArr.sort(function(a,b){return a.f - b.f;});//排序
   if(this.getEqual(this.closeArr,ePos.x,ePos.y) || this.getEqual(this.openArr,ePos.y)){//end
    this.minPath.unshift(this.closeArr[key]);
    while(this.minPath.length > 0){
     if(this.minPath[0].p == 0){return this.posts('success',this.minPath);}else{this.minPath.unshift(this.closeArr[this.minPath[0].p]);}
    }
   }else if(maxMachT === this.maxMach){
    return this.posts("沒有符合的座標");
   }
  }
  return this.posts("沒有符合的座標");
 }
 
}

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