使用reduce获取带有对象的object

Question

I have array of the following form:

[
{key: "key1", value: value1}
{key: "key2", value: value2}
{key: "key3", value: value3}
...
]

I need to convert to the following form:

{ { key1 : value1},  { key2 : value2},  { key3 : value3} } 

How to do it with reduce() ?

I am trying to use this code:

 var someObject = this.someArray.reduce(function(acc, item) {
            return { [item.key]: item.value};
        }, {});

but I always get only the last item instead of all of them.

Answer 1

The issue is in your return

return acc + { [item.key]: item.value};

You cannot use the + operator to add objects. Try the following:

acc[item.key] = item.value;
return acc

This assumes your keys are all unique. See full example below:

 let x = [{ key: "key1", value: 'value1' }, { key: "key2", value: 'value2' }, { key: "key3", value: 'value3' }, ].reduce((accumulatedValue, curentValue) => { accumulatedValue[curentValue.key] = curentValue.value; return accumulatedValue }, {}) console.log(x);

Answer 2

Either you seek an array of object, then the following example applies:

 const res = [{ key: 'key1', value: 'value1', }, { key: 'key1', value: 'value1', }, { key: 'key1', value: 'value1', }].reduce((tmp, { key, value, }) => [...tmp, { [key]: value, }, ], []); console.log(res);

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Either you seek an unique object, then the following example applies:

 const res = [{ key: 'key1', value: 'value1', }, { key: 'key2', value: 'value2', }, { key: 'key3', value: 'value3', }].reduce((tmp, { key, value, }) => ({...tmp, [key]: value, }), {}); console.log(res);

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About your code, as people told you already in the comments, you cannot simply use the + operator to concatenate either arrays or objects.