CODEWITHSUNDEEP
javascriptreduce
Honey Singh
Honey Singh

Reputation: 327

JavaScript Reduce with Objects

This is my object

   let products = [
      { "productName": "A", "storage": "Lot 1", "quantity": 1000, "status": "stockIn" },
      { "productName": "A", "storage": "Lot 1", "quantity": 100, "status": "stockIn"  },
      { "productName": "A", "storage": "Lot 1", "quantity": 500, "status": "stockOut" },
      { "productName": "A", "storage": "Lot 2", "quantity": 500, "status": "stockIn"  }
   ]

This is what I am trying to achieve

   let result = [
      { "productName": "A", "storage": "Lot 1", "stockIn": 1100, "stockOut": 500, "available":600 },
      { "productName": "A", "storage": "Lot 2", "stockIn": 500, "stockOut": 0, "available":500   }
   ]

Please kindly provide an idea on how to achieve this without redundant codes. Thanks

var storage = new Set(products.map(item => item.storage));

storage.forEach(lot => {

var stockIn = products.filter(item => item.storage === storage && item.status == 'stockIn')
    .map(({ storage, quantity }) => ({ storage, quantity }));

var stockInSum = stockIn.reduce((prev, curr, index) => prev + curr.quantity, 0);

var stockOut = products.filter(item => item.storage === storage && item.status == 'stockOut')
    .map(({ storage, quantity }) => ({ storage, quantity }))

var stockOutSum = stockOut.reduce((prev, curr, index) => prev + curr.quantity, 0);

}

Upvotes: 0

Views: 102

Answers (2)

Majed Badawi
Majed Badawi

Reputation: 28404

  • Using Array#reduce, iterate over the array while updating a Map where the key is the combination of productName and storage, and the value is the corresponding grouped object
  • In every iteration, using the current key, get the pair if exist and deconstruct stockIn and stockOut. According to the current status, update one of the latter values and compute available. Finally, using Map#set, create/update the pair.
  • Using Map#values, get the list of grouped objects

const products = [
  { productName: "A", storage: "Lot 1", quantity: 1000, status: "stockIn" },
  { productName: "A", storage: "Lot 1", quantity: 100,  status: "stockIn"  },
  { productName: "A", storage: "Lot 1", quantity: 500,  status: "stockOut" },
  { productName: "A", storage: "Lot 2", quantity: 500,  status: "stockIn"  }
];

const result = [...
  products.reduce((map, { productName, storage, quantity, status }) => {
    const key = `${productName}-${storage}`;
    let { stockIn = 0, stockOut = 0 } = map.get(key) ?? {};
    if(status === 'stockIn') stockIn += quantity;
    else stockOut += quantity;
    const available = stockIn - stockOut;
    map.set(key, { productName, storage, stockIn, stockOut, available });
    return map;
  }, new Map)
  .values()
];

console.log(result);

Upvotes: 1

Steven Spungin
Steven Spungin

Reputation: 29071

Here is the general pattern. I will leave it to you to figure out the other fields.

const reduced = products.reduce( (a,v) => {
  const found = a.find(it=>it.lot === v.lot && it.productName === v.productName)
  if (found) {
    a.quantity += v.quantity
    // aggregate your other fields here.
  }
  else {
    a.push(v)
  }
  return a
}, [] )

Upvotes: 0

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