I have an object like this :
obj = [{x:150, y:260},{x:160, y:545},{x:478, y:858},{x:125, y:560}]
and I want an array like this:
array = [150,260,160,545,478,858,125,560]
How can I do ?
6 Answers
Using flatMap()
const obj = [{x:150, y:260},{x:160, y:545},{x:478, y:858},{x:125, y:560}]
const res = obj.flatMap(Object.values)
console.log(res)
1 Comment
Peter Seliger
... .flatMap(Object.values) already is sufficient ... no need for the additional callback.You can use Array.prototype.reduce
const obj = [{x:150, y:260},{x:160, y:545},{x:478, y:858},{x:125, y:560}]
const arr = obj.reduce((acc, {x, y}) => acc.concat(x, y), [])
document.write(`arr = [${arr.join()}]`)as suggested in the comments to make it more generic you can
const obj = [{v: 100, x:150, y:260, z: 123},{x:160, y:545},{x:478, y:858},{x:125, y:560}]
const arr = obj.flatMap(Object.values)
document.write(`arr = [${arr.join()}]`)
3 Comments
briosheje
Huh, didn't think about
concat. Would there be any relevant difference instead of using push and returning the same array instead? that would be an interesting scenario.
Teneff
@briosheje probably in some cases
.push may have smaller memory usage, but with .concat is shorter because it returns the resulting arrayPeter Seliger
do you mind changing this approach into something more generic that takes unknown key value pairs into account.
try this:
[{x:150, y:260},{x:160, y:545},{x:478, y:858},{x:125, y:560}].flatMap(obj => [obj.x,obj.y])
Comments
Use reduce to make it in a single iteration. Otherwise, you can use map and flat or really many others, like flatMap.
Differently from map + flat or flatMap, reduce iterates the original array only once.
This likely is irrelevant in most scenarios, unless the array you're going to iterate is somewhat big.
const obj = [{x:150, y:260},{x:160, y:545},{x:478, y:858},{x:125, y:560}];
const array = obj.reduce((acc, next) => {
acc.push(...Object.values(next));
return acc;
}, []);
console.log(array);Comments
iterate over the array and concatenate the values into a new common array.
const obj = [{x:150, y:260},{x:160, y:545},{x:478, y:858},{x:125, y:560}];
let arr =[];
obj.forEach(function(item){
arr = arr.concat(Object.values(item));
})
console.log(arr)
Comments
In ES6 you can implement the following way using reduce and object destruction and array destruction:
const collection = [{x:150, y:260},{x:160, y:545},{x:478, y:858},{x:125, y:560}]
const arr = collection.reduce((acc, {x, y}) => [...acc, x, y], [])
console.log(arr)I'd say it is a collection not an object, so let's name it to collection not obj.
1 Comment
D. Pardal
What about
x?
[{x:150, y:260},{x:160, y:545}].reduce((collector, item) => collector.concat(Object.values(item)), []);... making use ofObject.valuesandArray.prototype.concat