How to covert an array of Object into Object with key and value as array

Question

I m looking for optimized solution using reddduced function to covert array of object to an object with values as an array

 const companies=[ {name:'Company One',email:'trishabh885@gmail.com',phone:'8860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'X Name',email:'grfgr@gmail.com',phone:'8860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'A one',email:'grfgt@yahoo.com',phone:'943548213', category:'Lecture',start:1981,end:2003,date:'21-06-2009'}, {name:' Name',email:'gtrgt@gmail.com',phone:'9656013653', category:'Finance',start:1981,end:2003}, {name:'Company Name',email:'grgtrgg@gmail.com', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'sdksdjd',email:'bfbrg@gbmail.com',phone:'7485788475898548', category:'Sciennce',start:1981,end:2003,date:'21-06-2009'}, {name:'kdjfkf',email:'gfggfb@gmail.com',phone:'0959898860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'vdjf',email:'g5rgf@gmail.com',phone:'050498860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'vdjvk',email:'trishabh885@gmail.com',phone:'958958860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'vdkv',email:'trishabh885@gmail.com',phone:'5434886013821543543', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'zeeshan',email:'trishabh885@gmail.com',phone:'8864535213', category:'Finance',start:1981,end:2003,date:'21-06-2009'} ] // Looking for better and optimised solution to convert array of object into object with. values as an array using map methods let reduced_object={} let reduced_array=companies.reduce((arr,current)=>{ let entries=Object.entries(current) entries.forEach(element=>{ if(reduced_object.hasOwnProperty(element[0])){ reduced_object[element[0]].push(element[1]) }else{ reduced_object[element[0]]=[element[1]]; } }) return reduced_object }) console.log(reduced_array)

Answer 1

This solution does not use reducing:

let obj = {
  name: companies.map(item => item.name).filter(value => value !== undefined),
  email: companies.map(item => item.email).filter(value => value !== undefined),
  phone: companies.map(item => item.phone).filter(value => value !== undefined),
  category: companies.map(item => item.category).filter(value => value !== undefined),
  start: companies.map(item => item.start).filter(value => value !== undefined),
  end: companies.map(item => item.end).filter(value => value !== undefined),
  date: companies.map(item => item.date).filter(value => value !== undefined)
}

Edit: Added filters to remove 'undefined' entries when properties are missing in the source.

Answer 2

I would use map instead:

// ...
const reduced_object = {};
reduced_object.name = companies.map(item => item.name);
reduced_object.email = companies.map(item => item.email);
reduced_object.phone = companies.map(item => item.phone);
// ...

Of course, once you know (or determine) the list of keys of each item, you can wrap it up in a for-of loop:

// ...
const reduced_object = {};
for (let key of item_keys) {
    reduced_object[key] = companies.map(item => item[key]);
}

Answer 3

Another solution:

 const companies=[ {name:'Company One',email:'trishabh885@gmail.com',phone:'8860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'X Name',email:'grfgr@gmail.com',phone:'8860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'A one',email:'grfgt@yahoo.com',phone:'943548213', category:'Lecture',start:1981,end:2003,date:'21-06-2009'}, {name:' Name',email:'gtrgt@gmail.com',phone:'9656013653', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'Company Name',email:'grgtrgg@gmail.com',phone:'954543656138256', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'sdksdjd',email:'bfbrg@gbmail.com',phone:'7485788475898548', category:'Sciennce',start:1981,end:2003,date:'21-06-2009'}, {name:'kdjfkf',email:'gfggfb@gmail.com',phone:'0959898860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'vdjf',email:'g5rgf@gmail.com',phone:'050498860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'vdjvk',email:'trishabh885@gmail.com',phone:'958958860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'vdkv',email:'trishabh885@gmail.com',phone:'5434886013821543543', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'zeeshan',email:'trishabh885@gmail.com',phone:'8864535213', category:'Finance',start:1981,end:2003,date:'21-06-2009'} ] const arr = companies.reduce((acc, company) => ({ ...acc, ...Object.entries(company).reduce((objAcc, [key, val]) => ({ ...objAcc, [key]: [...acc?.[key] ?? [], ...val ? [val] : []] }), {}) }), {}) console.log(arr)

If you don't want to have duplicate values you can also do this:

 const companies=[ {name:'Company One',email:'trishabh885@gmail.com',phone:'8860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'X Name',email:'grfgr@gmail.com',phone:'8860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'A one',email:'grfgt@yahoo.com',phone:'943548213', category:'Lecture',start:1981,end:2003,date:'21-06-2009'}, {name:' Name',email:'gtrgt@gmail.com',phone:'9656013653', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'Company Name',email:'grgtrgg@gmail.com',phone:'954543656138256', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'sdksdjd',email:'bfbrg@gbmail.com',phone:'7485788475898548', category:'Sciennce',start:1981,end:2003,date:'21-06-2009'}, {name:'kdjfkf',email:'gfggfb@gmail.com',phone:'0959898860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'vdjf',email:'g5rgf@gmail.com',phone:'050498860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'vdjvk',email:'trishabh885@gmail.com',phone:'958958860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'vdkv',email:'trishabh885@gmail.com',phone:'5434886013821543543', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'zeeshan',email:'trishabh885@gmail.com',phone:'8864535213', category:'Finance',start:1981,end:2003,date:'21-06-2009'} ] const arr = companies.reduce((acc, company) => ({ ...acc, ...Object.entries(company).reduce((objAcc, [key, val]) => ({ ...objAcc, [key]: [...new Set([...acc?.[key] ?? [], ...val ? [val] : []])] }), {}) }), {}) console.log(arr)

Answer 4

The fun functional route:

[...new Set(companies.flatMap(Object.keys))]
    .reduce((result, key) => {result[key] = companies.map(c => c[key]); return result;}, {})

The first line finds all the keys. The second line creates the desired result. But honestly, in real life, I would skip that reduce and write a simple for loop. I would always pick clarity over "functional purity".

Answer 5

With simple forEach loops, iterate and check for each item.

 const process = (arr, output = {}) => { companies.forEach((obj) => Object.entries(obj).forEach(([key, value]) => (output[key] ||= []).push(value) ) ); return output; }; const companies=[ {name:'Company One',email:'trishabh885@gmail.com',phone:'8860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'X Name',email:'grfgr@gmail.com',phone:'8860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'A one',email:'grfgt@yahoo.com',phone:'943548213', category:'Lecture',start:1981,end:2003,date:'21-06-2009'}, {name:' Name',email:'gtrgt@gmail.com',phone:'9656013653', category:'Finance',start:1981,end:2003}, {name:'Company Name',email:'grgtrgg@gmail.com', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'sdksdjd',email:'bfbrg@gbmail.com',phone:'7485788475898548', category:'Sciennce',start:1981,end:2003,date:'21-06-2009'}, {name:'kdjfkf',email:'gfggfb@gmail.com',phone:'0959898860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'vdjf',email:'g5rgf@gmail.com',phone:'050498860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'vdjvk',email:'trishabh885@gmail.com',phone:'958958860138213', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'vdkv',email:'trishabh885@gmail.com',phone:'5434886013821543543', category:'Finance',start:1981,end:2003,date:'21-06-2009'}, {name:'zeeshan',email:'trishabh885@gmail.com',phone:'8864535213', category:'Finance',start:1981,end:2003,date:'21-06-2009'} ] console.log(process(companies))