How to add a lable to an object value in javascript-CodePudding

I have an array of objects that is grouped by index and would like to restructure and add labels to the response.

This is my original array:

let cars = [{'make': 'audi', 'model': 'RS3', 'transmition': 'automatic'}, {'make': 'audi', 'model': 'RS7', 'transmition': 'dual-clutch'}, {'make': 'bmw', 'model': '325is', 'transmition': 'manual'}, {'make': 'bmw', 'model': 'M2', 'transmition': 'dual-clutch'}]

Here is the source code used to group the array by make:

var groupedByMake = _.groupBy(
          cars,
          "make"
        );

The response looks like this:

{
  'audi':[{'model': 'RS3', 'transmition': 'automatic'}, {'model': 'RS7', 'transmition': 'dual-clutch'}],
  'bmw':[{'model': '325is', 'transmition': 'manual'}, {'model': 'M2', 'transmition': 'dual-clutch'}]
}

My desired outcome should look like this:

[{
  'make': 'audi',
   'types': [{'model': 'RS3', 'transmition': 'automatic'}, {'model': 'RS7', 'transmition': 'dual-clutch'}]
  },{
  'make': 'bmw',
  'types': [{'model': '325is', 'transmition': 'manual'}, {'model': 'M2', 'transmition': 'dual-clutch'}]
}]

Is this possible to achieve using JavaScript? If so can I get assistance to achieve this task.

CodePudding user response：

You can use array.reduce to turn one array into another one and control whether you return a new element or accumulate values in existing one (prev):

let cars = [{'make': 'audi', 'model': 'RS3', 'transmition': 'automatic'}, {'make': 'audi', 'model': 'RS7', 'transmition': 'dual-clutch'}, {'make': 'bmw', 'model': '325is', 'transmition': 'manual'}, {'make': 'bmw', 'model': 'M2', 'transmition': 'dual-clutch'}];

let output = cars.reduce((acc, cur) => {
    let {make, ...obj} = cur;    
    let prev = acc.find(x => x.make === make);
    if(!prev) {
      acc.push({make,types:[obj]})
    } else {
      prev.types.push(obj);
    }
    return acc;
}, []);

console.log(output);

CodePudding user response：

const cars = [{'make': 'audi', 'model': 'RS3', 'transmition': 'automatic'}, {'make': 'audi', 'model': 'RS7', 'transmition': 'dual-clutch'}, {'make': 'bmw', 'model': '325is', 'transmition': 'manual'}, {'make': 'bmw', 'model': 'M2', 'transmition': 'dual-clutch'}];
const groupBy = (array, key) => {
  return array.reduce((acc, item) => {
    const keyValue = item[key];
    const existingGroup = acc.find((group) => group.key === keyValue);
    if (existingGroup) {
      existingGroup.items.push(item);
    } else {
      // remove make from item
      const { make, ...rest } = item;
      acc.push({ key: keyValue, items: [rest] });
    }
    return acc;
  }, []);
}


console.log(JSON.stringify(groupBy(cars, 'make'), null, 2));

CodePudding user response：

If you want to keep your groupby as-is (using lodash):

  // Result from lodash
var groupedByMake = {
  'audi':[{'model': 'RS3', 'transmition': 'automatic'}, {'model': 'RS7', 'transmition': 'dual-clutch'}],
  'bmw':[{'model': '325is', 'transmition': 'manual'}, {'model': 'M2', 'transmition': 'dual-clutch'}]
}

const result = Object.keys(groupedByMake).map(make => ({make, types: groupedByMake [make]}));

console.log(result);