如何在 JavaScript 中转换对象数组？

Question

I need to transform array of objects in a way that an object with same service stores all the total_costs in a single array.

So array of objects, each object contains array of total_costs with same service So, from:

[ 
     { total_costs: 263.6372995531,
       service: '136981853692',
       date_fields: '2018-04-02T00:00:00' },
     { total_costs: 121.3059868476,
       service: '136981853693',
       date_fields: '2018-04-16T00:00:00' },
     { total_costs: 105.6087751695,
       service: '136981853693',
       date_fields: '2018-04-23T00:00:00' },
     { total_costs: 8.7002453728,
       service: '136981853693',
       date_fields: '2018-04-30T00:00:00' } ]

Into:

 [
    {
      "service": "136981853693",
      "total_costs" : [8.7002453728, 105.6087751695, 121.3059868476...]
    },
    {
      "service": "136981853692",
      "total_costs" : [263.6372995531]
    }
  ]

How can I do it?

Answer 1

Use reduce to group into an object indexed by the service property, and then get that object's values:

 const input=[{total_costs:263.6372995531,service:'136981853692',date_fields:'2018-04-02T00:00:00'},{total_costs:121.3059868476,service:'136981853693',date_fields:'2018-04-16T00:00:00'},{total_costs:105.6087751695,service:'136981853693',date_fields:'2018-04-23T00:00:00'},{total_costs:8.7002453728,service:'136981853693',date_fields:'2018-04-30T00:00:00'}]; const output = Object.values( input.reduce((a, { total_costs, service }) => { if (!a[service]) a[service] = { service, total_costs: [] }; a[service].total_costs.push(total_costs); return a; }, {}) ); console.log(output);