javascript - 数组(推-对象)未按预期工作

Question

我在将对象插入数组时遇到问题。我设置了一个带有值的对象并将它们推送到数组中。然后，我更改对象的一些值并将对象再次插入数组中。但是，经过检查，插入数组的两个对象是相同的，两个对象的值都与插入数组的最后一个对象相同。

let ProductPosition = function (x, y) {
    this.x = x;
    this.y = y;
}

let PalletType = (function () {
    function PalletType() {
        this.PatternType = '';
        this.ProductWidth = 0;
        this.PalletWidth = 0;
        this.ProductPositions = [];
    }
});

function getPalletPositions(pallet, pattern) {
    pal.ProductPositions = [];
    let posn = new ProductPosition();
    switch (pattern) {
        case '1U1':
            posn = [];
            posn.y = pal.PalletWidth / 2;
            posn.angle = 0;
            posn.apprDir = 0;
            pallet.ProductPositions.push(posn);
            break;
        case '2U1':
            posn = [];
            posn.y = pal.PalletWidth / 2 + pal.ProductWidth / 2;
            console.log('y pos 0 ' + posn.y);
            pal.ProductPositions.push(posn);//first push

            posn.y = pal.PalletWidth / 2 - pal.ProductWidth / 2;
            console.log('y pos 1 ' + posn.y);
            pallet.ProductPositions.push(posn);//first push
            break;
    }
}
let pal = new PalletType();

pal.PalletWidth = 1165;
pal.ProductWidth = 400
let pat = '2U1';

getPalletPositions(pal, pat);

pal.ProductPositions.forEach(function (pos) {
    console.log("pos.y:" + pos.y);
});

实际输出:

y pos 0 782.5 <-value of y of first push
y pos 1 382.5 <-value of y of second push
pos.y:382.5   <-should be 782.5
pos.y:382.5

我期望:

y pos 0 782.5 <-value of y of first push
y pos 1 382.5 <-value of y of second push
pos.y:782.5
pos.y:382.5

我完全困惑并尝试了一些方法，但无济于事。

Answer 1

您正在改变可以使用的对象 spread运算符或Object.assign

检查下面

let ProductPosition = function (x, y) {
    this.x = x;
    this.y = y;
}

let PalletType = (function () {
    function PalletType() {
        this.PatternType = '';
        this.ProductWidth = 0;
        this.PalletWidth = 0;
        this.ProductPositions = [];
    }
});

function getPalletPositions(pallet, pattern) {
    pal.ProductPositions = [];
    let posn = new ProductPosition();
    debugger;
    switch (pattern) {
        case '1U1':
            posn = [];
            posn.y = pal.PalletWidth / 2;
            posn.angle = 0;
            posn.apprDir = 0;
            pallet.ProductPositions.push(posn);
            break;
        case '2U1':
            posn = [];
            posn.y = pal.PalletWidth / 2 + pal.ProductWidth / 2;
            console.log('y pos 0 ' + posn.y);
            pal.ProductPositions.push({...posn});//first push

            posn.y = pal.PalletWidth / 2 - pal.ProductWidth / 2;
            console.log('y pos 1 ' + posn.y);
            pallet.ProductPositions.push({...posn});//first push
            break;
    }
}
let pal = new PalletType();

pal.PalletWidth = 1165;
pal.ProductWidth = 400
let pat = '2U1';

getPalletPositions(pal, pat);

pal.ProductPositions.forEach(function (pos) {
    console.log("pos.y:" + pos.y);
});