如何使用 reduce 将对象数组转换为单个 object？

Question

I have the following array of object.

[
  { claimNumber1: 'R12345', checkNumber1: '' },
  { claimNumber2: 'T1234', checkNumber2: 'abcd' },
  { claimNumber3: 'Z4567', checkNumber3: 'qwer' }
]

Using reduce , I want to convert this to below.

{
    claimNumber1:'R12345',
    checkNumber1:'',
    claimNumber2:'T1234',
    checkNumber2:'',
    claimNumber3:'Z4567',
    checkNumber3:'',

}

I tried below but didn't get what I expected.

.reduce((obj, item) =>{
    return {...obj,item}
} ,{});

Answer 1

You should spread the item object, because item is an object

 const arr = [ { claimNumber1: "R12345", checkNumber1: "" }, { claimNumber2: "T1234", checkNumber2: "abcd" }, { claimNumber3: "Z4567", checkNumber3: "qwer" }, ]; const result = arr.reduce((obj, item, i) => { return {...obj, ...item, [`checkNumber${i + 1}`]: "" }; }, {}); console.log(result);

Answer 2

Almost there. You just need to spread the item as well.

.reduce((obj, item) => {
  return {
    ...obj,
    ...item,
  };
}, {});

Answer 3

I think you should spread every item in reducer. Here is my code.

const res = arr.reduce((prev, item) => {
 return { ...prev, ...item };
}, {});

And result is

{
  claimNumber1: 'R12345',
  checkNumber1: '',
  claimNumber2: 'T1234',
  checkNumber2: 'abcd',
  claimNumber3: 'Z4567',
  checkNumber3: 'qwer'
}

Answer 4

I'm not sure of the benefit of using reduce in this situation. A simple loop would be self-documenting, and easier to read.

 const data = [ { claimNumber1: 'R12345', checkNumber1: '' }, { claimNumber2: 'T1234', checkNumber2: 'abcd' }, { claimNumber3: 'Z4567', checkNumber3: 'qwer' } ]; const out = {}; // For every object in the array for (const obj of data) { // Get an array of its keys and iterate over them for (const key of Object.keys(obj)) { // If it's a claim add that value to the output // object property, otherwise set that property value // to an empty string. if (key.startsWith('claim')) { out[key] = obj[key]; } else { out[key] = ''; } } } console.log(out);

Additional documentation

• Object.keys