I want to create object from list of array. I have an array which is dynamic which suppose to be look like this:
var dynamicArray = ["2007", "2008", "2009", "2010"];
and with some javascript es6 I want to make an object like this:
const obj = {
2007: {
x: width / 5,
y: height / 2
},
2008: {
x: (2 / 5) * width,
y: height / 2
},
2009: {
x: (3 / 5) * width,
y: height / 2
},
2010: {
x: (4 / 5) * width,
y: height / 2
}
}
don't worry about inner objects but just wanted to a make structure like this:
obj = {
2007: ...,
2008: ...,
...
}
Please help, Thanks.
Simply
const obj = {};
for (const key of yourArray) {
obj[key] = whatever;
}
or if you prefer "functional" style:
const obj = yourArray.reduce((o, key) => Object.assign(o, {[key]: whatever}), {});
using the modern object spread operator:
const obj = yourArray.reduce((o, key) => ({ ...o, [key]: whatever}), {})
Example:
[
{ id: 10, color: "red" },
{ id: 20, color: "blue" },
{ id: 30, color: "green" }
].reduce((acc, cur) => ({ ...acc, [cur.color]: cur.id }), {})
Output:
{red: 10, blue: 20, green: 30}
Here is how it works:
reduce
is initialized with an empty object (empty {}
at the end), therefore first iteration variables are acc = {}
cur = { id: 10, color: "red" }
. Function returns an object - this is why function body is wrapped in parentheses => ({ ... })
. Spread operator doesn't do anything on the first iteration, so red: 10
is set as first item.
On the second iteration variables are acc = { red: 10 }
cur = { id: 20, color: "blue" }
. Here the spread operator expands acc
and the function returns { red: 10, blue: 20 }
.
Third iteration acc = { red: 10, blue: 20 }
cur = { id: 30, color: "green" }
, so when acc
is spread inside the object, our function returns the final value.