如何在数组中找到具有相同键值的对象？

Question

I have an array of objects that looks like this:

  const arr = [
    { type: 'type', fields: ['field1'] },
    { type: 'type2' },
    { type: 'type', fields: ['field2'] },
  ]

And I need to find objects with the same type to merge fields key in them, like this:

  const arr = [
    { type: 'type', fields: ['field1', 'field2'] },
    { type: 'type2' },
    { type: 'type', fields: ['field1', 'field2'] },
  ]

My plan was to filter through the array, but my problem is that I don't know which type will send me API, so filtering by item.type wouldn't work for me.

Answer 1

If that is the exact solution that you want. Following code snippet may help you.

    const arr = [
      { type: 'type', fields: ['field1']},
      { type: 'type2'},
      { type: 'type', fields: ['field2']}
    ]
    
    const modifyArr = (data) => {
      let res = [];
      arr.map((item) => {
          if(item.type == data.type){
            if(Object.keys(item).includes('fields')){
              res = res.concat(item.fields);
            }
          }
      });
      return Object.keys(data).includes('fields') ? { type: data.type, fields: res } : { type: data.type };

}

let newArr = arr.map(item => modifyArr(item));

console.log(newArr); 

This will print

[
    { type: 'type', fields: ['field1', 'field2'] },
    { type: 'type2' },
    { type: 'type', fields: ['field1', 'field2'] },
  ]

Answer 2

 const arr = [{ type: 'type', fields: ['field1']}, { type: 'type2'}, { type: 'type', fields: ['field2']}]; result = arr.map(({ type }) => { const fields = arr.filter((o) => o.type === type).flatMap((e) => e.fields); return { type, ...fields[0]? { fields }: {} }; }); console.log(result); //[ // {"type": "type", "fields": ["field1", "field2"]}, // {"type": "type2"}, // {"type": "type", "fields": ["field1", "field2"]} //]