我正在嘗試使用“節點”類建構式創建一個物件陣列。每個節點都應該有一個包含相鄰節點的陣列。當我使用 for 回圈遍歷每個 Node 以添加鄰居時，它會觸發類方法，但 Node 物件無法更新。
這是我正在做的人為/簡化版本：
export default class Node {
neighbours: Node[];
addNeighbours: (thisNode: Node) => void;
constructor() {
this.neighbours = [];
this.addNeighbours = function (thisNode: Node) {
thisNode.neighbours = []
this.neighbours.push(thisNode)
console.log(this.neighbours.length); // returns 1. So this is being triggered and appears to be working.
}
}
}
// Create an array to represent the 2D grid.
export function createArrayOfNodes(): Node[][] {
let returnGrid: Node[][] = [
[new Node(), new Node(), new Node()],
[new Node(), new Node(), new Node()],
[new Node(), new Node(), new Node()],
]
// add neighbours to each Node
for (let i = 0; i < returnGrid.length; i ) {
for (let j = 0; j < returnGrid.length; j ) {
const newJ = j 1 === returnGrid.length ? 0 : j 1
returnGrid[i][j].addNeighbours(returnGrid[i][newJ]); // This fails to add a neighbour
// returnGrid[i][j].addNeighbours(new Node()); // This adds a neighbour OK
}
}
// returnGrid[0][0].addNeighbours(returnGrid[0][1]); // This adds a neighbour OK
return returnGrid;
}
console.log(createArrayOfNodes) // Returns an array of Nodes, but they don't have any Nodes in their neighbour properties.
根據注釋掉的代碼，neighbours如果屬性在for回圈之外，我可以更新它。如果我在for回圈中，我可以在neighbours創建新節點時更新屬性，但如果我嘗試從returnGrid. 誰能解釋一下？
uj5u.com熱心網友回復：
似乎以下行使您的代碼不起作用。評論它一切正常。
thisNode.neighbours = [];
節點應如下所示
export default class Node {
neighbours: Node[];
addNeighbours: (thisNode: Node) => void;
constructor() {
this.neighbours = [];
this.addNeighbours = function (thisNode: Node) {
this.neighbours.push(thisNode);
};
}
}
實際上，您可以定義addNeighbours建構式的外部。
export default class Node {
neighbours: Node[];
constructor() {
this.neighbours = [];
}
addNeighbours = function (thisNode: Node) {
this.neighbours.push(thisNode);
};
}
作業示例，
uj5u.com熱心網友回復：
每次呼叫該addNeighbours方法時，都會重新分配neighbours傳遞的陣列Node。這將有效地重置neighbours傳遞的陣列Node。
洗掉thisNode.neighbours = []線。
class Node {
neighbours = [];
addNeighbours(thisNode) {
this.neighbours.push(thisNode)
}
}
// Create an array to represent the 2D grid.
function createArrayOfNodes() {
let returnGrid = [
[new Node(), new Node(), new Node()],
[new Node(), new Node(), new Node()],
[new Node(), new Node(), new Node()],
]
// add neighbours to each Node
for (let i = 0; i < returnGrid.length; i ) {
for (let j = 0; j < returnGrid.length; j ) {
const newJ = j 1 === returnGrid.length ? 0 : j 1
returnGrid[i][j].addNeighbours(returnGrid[i][newJ]);
}
}
return returnGrid;
}
console.log(createArrayOfNodes());旁注：我注意到你是如何在你的Node類上宣告你的屬性和方法的。您可以分配每個實體應在class范圍內繼承的屬性和方法，而不是constructor.
可constructor用于在實體化類時斷言邏輯和處理引數。
export default class Node {
neighbours: Node[] = [];
addNeighbours(thisNode: Node): void {
this.neighbours.push(thisNode)
}
}
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標籤：javascript 打字稿 循环 班级
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