Extract JSON value using array.map()

Question

I'm trying to extract specific value from JSON object using the following code:

 data: any[] = [
    {'id': 1, 'expenseType': {'id': 1, 'name': 'type1'} , 'cost': 100},
    {'id': 2, 'expenseType': {'id': 2, 'name': 'type2'}, 'cost': 200 },
    {'id': 3, 'expenseType': {'id': 3, 'name': 'type3'}, 'cost': 300} }
];

 filterData = this.data.map(({ expenseType }) => ({
   expenseType   
 }));

I want the filterData to be an array of:

[{'id': 1, 'name': 'type1'},{'id': 2, 'name': 'type2'}, {'id': 3, 'name': 'type3']

The problem is that the key is also included.

Can I achieve this using array.map()?

If you don't want another object, why do you build one? Either copy (`=> ({ ...expenseType })`, see *"destructuring"*) or just return (`=> expenseType`) the object you want. — jonrsharpe, Feb 10 '20 at 08:41

score 5 · Accepted Answer · answered Feb 10 '20 at 08:42

You need just to return expenseType, without using it as short hand property.

var data = [{ id: 1, expenseType: { id: 1, name: 'type1' }, cost: 100  }, { id: 2, expenseType: { id: 2, name: 'type2' }, cost: 200 }, { id: 3, expenseType: { id: 3,  name: 'type3' }, cost: 300 }],
    filterData = data.map(({ expenseType }) => expenseType);

console.log(filterData);

Extract JSON value using array.map()

1 Answers1