I have an array of objects like this:
let someObj = {
items: [{
id: '12',
value: true
}, {
id: '34',
value: true
}, {
id: '56',
value: false
}]
}
I want add this to an exiting object, where id is a key of this object, like this:
let obj = {
someKey: someValue,
'12': true,
'34': true,
'56': false,
}
You may achieve your goal using Array#reduce as follows:
const input = {
items: [{
id: '12',
value: true
}, {
id: '34',
value: true
}, {
id: '56',
value: false
}]
}
const output = input.items.reduce((o, {
id,
value
}) => (o[id] = value, o), {})
console.log(output)Also, and maybe the simplest approach might be using Array#map to turn objects into pairs and then convert them into an object using Object.fromPairs:
const input = {
items: [{
id: '12',
value: true
}, {
id: '34',
value: true
}, {
id: '56',
value: false
}]
}
const output = Object.fromEntries(input.items.map(({
id,
value
}) => [id, value]))
console.log(output)Finally, here's a functional approach:
// Composes two functions
const compose = f => g => x => f (g (x))
// Given the key-value pairs of some object with 2 properties, maps a pair of values
const values = ([[, x], [, y]]) => [x, y]
// Turns an object of two properties into a pair of property values
const entry = compose (values) (Object.entries)
// Turns many objects of two properties, into an object on which
// keys are first properties' values, and vaules the second properties' values.
const keyValueObject = xs => Object.fromEntries (xs.map (entry))
const input = {
items: [{
id: '12',
value: true
}, {
id: '34',
value: true
}, {
id: '56',
value: false
}]
}
const output = keyValueObject (input.items)
console.log(output)
You can iterate each item from items and create a new object as shown below.
let someObj = {
items: [{
id: '12',
value: true
}, {
id: '34',
value: true
}, {
id: '56',
value: false
}]
}
const newObj = {};
someObj.items.map(item =>{
newObj[item.id]= item.value;
});
console.log(newObj);Use map and Object.values will simplify.
const output = arr => Object.fromEntries(arr.map(Object.values));
let someObj = {
items: [
{
id: "12",
value: true,
},
{
id: "34",
value: true,
},
{
id: "56",
value: false,
},
],
};
console.log(output(someObj.items));
First, you can transform the itens into "KV" entries
> someObj.items.map(({id, value}) => [id, value])
[ [ '12', true ], [ '34', true ], [ '56', false ] ]
Then turn it into Object
> Object.fromEntries(someObj.items.map(({id, value}) => [id, value]))
{ '12': true, '34': true, '56': false }
You can do a function
> let ObjectFromMapping = (vs, mapping) => Object.fromEntries(vs.map(mapping))
> ObjectFromMapping(someObj.items, ({id, value}) => [id, value])
{ '12': true, '34': true, '56': false }
Maybe turn vs into a iterable is a good idea
> let ObjectFromMapping = (vs, mapping) => Object.fromEntries([... vs].map(mapping))
> ObjectFromMapping("abc", (char, idx) => [idx, char])
{ '0': 'a', '1': 'b', '2': 'c' }
Then your function will work on any iterable
