Array of objects to another array sumarized-CodePudding

I'm new to JS and I'm having issues to sum values from one array into another one summarized.

I have this data:

const data = [
  {
    category: 'personal',
    amount: 80000,
    month: 'Diciembre',
  },
  {
    category: 'comida',
    amount: 207000,
    month: 'Diciembre',
  },
  {
    category: 'comida',
    amount: 43000,
    month: 'Diciembre',
  },
  {
    category: 'salidas',
    amount: 124000,
    month: 'Diciembre',
  },
  {
    category: 'casa',
    amount: 450505,
    month: 'Diciembre',
  },
  {
    category: 'casa',
    amount: 500000,
    month: 'Diciembre',
  },
  {
    category: 'varios',
    amount: 260000,
    month: 'Diciembre',
  },
  {
    category: 'casa',
    amount: 296300,
    month: 'Diciembre',
  },
];

And I want to convert it in something like:

const dataSummarized = [
  {
    category: 'personal',
    amount: TOTAL_AMOUNT_PERSONAL_CATEGORY
    month: 'Diciembre',
  },
  {
    category: 'comida',
    amount: TOTAL_AMOUNT_COMIDA_CATEGORY
    month: 'Diciembre',
  },
  {
    category: 'salidas',
    amount: TOTAL_AMOUNT_SALIDAS_CATEGORY,
    month: 'Diciembre',
  },
  {
    category: 'casa',
    amount: TOTAL_AMOUNT_CASA_CATEGORY,
    month: 'Diciembre',
  }
];

I've tried several options, but without results.

Some of the solutions I've tried are posted here Sum javascript object propertyA values with same object propertyB in array of objects

Evidently, I'm missing something because I couldn't make it work :(

Thanks in advance!

CodePudding user response：

We can then use Array.reduce() to group items by category, then month (I presume you want expense totals per month).

We create a grouping key based on category and month, then sum the total amount for each of these keys:

const data = [ { category: 'personal', amount: 80000, month: 'Diciembre', }, { category: 'comida', amount: 207000, month: 'Diciembre', }, { category: 'comida', amount: 43000, month: 'Diciembre', }, { category: 'salidas', amount: 124000, month: 'Diciembre', }, { category: 'casa', amount: 450505, month: 'Diciembre', }, { category: 'casa', amount: 500000, month: 'Diciembre', }, { category: 'varios', amount: 260000, month: 'Diciembre', }, { category: 'casa', amount: 296300, month: 'Diciembre', }, ]; 

const result = Object.values(data.reduce((acc, { category, month, amount }) => { 
    const key = `${category}-${month}`;
    acc[key] = acc[key] || { category, month, amount: 0 };
    acc[key].amount  = amount;
    return acc;
}, {}));

console.log('Result:', result);

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