adding values in array where id's are the same-CodePudding

(14) [{…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}]
0: {itemId: 'F4', itemRate: 20, Amount: 20, itemName: 'Kesar pista', itemQuantity: 1}
1: {itemName: 'Vegetable manchuri', itemRate: 60, itemId: 'G5', Amount: 120, itemQuantity: 2}
2: {itemRate: 50, Amount: 50, itemQuantity: 1, itemId: 'C10', itemName: 'Dry fruit '}
3: {itemId: 'C3', itemRate: 40, itemQuantity: 1, Amount: 40, itemName: 'Butter scotch'}
4: {itemName: 'Panner sandwich   milk shake', Amount: 90, itemId: 'CS4', itemRate: 90, itemQuantity: 1}
5: {itemQuantity: 1, itemId: 'B5', itemRate: 70, Amount: 70, itemName: 'Panner burger'}
6: {itemId: 'C10', itemQuantity: 1, Amount: 50, itemName: 'Dry fruit ', itemRate: 50}
7: {itemQuantity: 2, itemName: 'American nuts', Amount: 100, itemRate: 50, itemId: 'C8'}
8: {itemName: 'Mango ', Amount: 50, itemQuantity: 1, itemId: 'C7', itemRate: 50}
9: {Amount: 40, itemId: 'C6', itemQuantity: 1, itemName: 'Choclate ', itemRate: 40}
10: {itemRate: 40, itemId: 'C3', itemQuantity: 1, Amount: 40, itemName: 'Butter scotch'}
11: {itemRate: 45, itemId: 'B1', itemName: 'Veg burger', Amount: 45, itemQuantity: 1}
12: {itemName: 'Veg cheese', Amount: 55, itemId: 'B2', itemQuantity: 1, itemRate: 55}
13: {itemName: 'Vanila', itemQuantity: 1, itemId: 'C1', Amount: 30, itemRate: 30}
length: 14
[[Prototype]]: Array(0)

I have a array. In the array there are 2 [id] values that are the same. I want to add the quantity,rate of these elements and merge the elements where the [id] are the same using javascript. I had tried following method but it shows wrong value.

 let result = Object.values(this.orderDetail.reduce((c, {itemId,itemRate,itemQuantity,itemName}) => {
              c[itemId] = c[itemId] || {itemId,itemRate,itemQuantity,itemName: 0};
              c[itemId].itemRate  = itemRate;
              c[itemId].itemQuantity  = itemQuantity;
              c[itemId].itemName = itemName;
              return c;
            }, {}));

result

CodePudding user response：

As I looked into the result, there is one extra time all values are passing into it. I guess you should try passing default values zero or an empty string to it.

CodePudding user response：

The issue is with the first line in the accumulator.

c[itemId] = c[itemId] || {itemId,itemRate,itemQuantity,itemName: 0};

You should assign the initial values here. This should be as below

c[itemId] = c[itemId] || { itemId, itemRate: 0, itemQuantity: 0, itemName: '', Amount: 0 };

Or else, you will be adding the first value twice to the accumulator.

Working Fiddle

const data = [{ itemId: 'F4', itemRate: 20, Amount: 20, itemName: 'Kesar pista', itemQuantity: 1 },
  { itemId: 'G5', itemName: 'Vegetable manchuri', itemRate: 60, Amount: 120, itemQuantity: 2 },
  { itemId: 'C10', itemRate: 50, Amount: 50, itemQuantity: 1, itemName: 'Dry fruit ' },
  { itemId: 'C3', itemRate: 40, itemQuantity: 1, Amount: 40, itemName: 'Butter scotch' },
  { itemId: 'CS4', itemName: 'Panner sandwich   milk shake', Amount: 90, itemRate: 90, itemQuantity: 1 },
  { itemId: 'B5', itemQuantity: 1, itemRate: 70, Amount: 70, itemName: 'Panner burger' },
  { itemId: 'C10', itemQuantity: 1, Amount: 50, itemName: 'Dry fruit ', itemRate: 50 },
  { itemId: 'C8', itemQuantity: 2, itemName: 'American nuts', Amount: 100, itemRate: 50 },
  { itemId: 'C7', itemName: 'Mango ', Amount: 50, itemQuantity: 1, itemRate: 50 },
  { itemId: 'C6', Amount: 40, itemQuantity: 1, itemName: 'Choclate ', itemRate: 40 },
  { itemId: 'C3', itemRate: 40, itemQuantity: 1, Amount: 40, itemName: 'Butter scotch' },
  { itemId: 'B1', itemRate: 45, itemName: 'Veg burger', Amount: 45, itemQuantity: 1 },
  { itemId: 'B2', itemName: 'Veg cheese', Amount: 55, itemQuantity: 1, itemRate: 55 },
  { itemId: 'C1', itemName: 'Vanila', itemQuantity: 1, Amount: 30, itemRate: 30 },
];

let result = Object.values(data.reduce((c, { itemId, itemRate, itemQuantity, itemName, Amount }) => {
  const temp = { itemId, itemRate: 0, itemQuantity: 0, itemName: '', Amount: 0 };
  c[itemId] = c[itemId] || temp;
  c[itemId].itemRate  = itemRate;
  c[itemId].itemQuantity  = itemQuantity;
  c[itemId].itemName = itemName;
  c[itemId].Amount  = Amount;
  return c;
}, {}));
console.log(result);