Reduce method is not easy, help me with this problem pls.
i need a function, that receive array with anything, and returns object with fields
{field1, field2, field3, field4}
like in the example: Input:
[true,6,'wow','you are smart, bro']
Output:
{field1: true, field2:1, field3: 'wow', field4: 'you are smart, bro'}
A solution that uses Object.fromEntries (browsers that support ECMAScript 2019 only):
const arr = [true, 6, 'wow', 'you are smart, bro'];
const result = Object.fromEntries(arr.map((x, i) => [`field${i + 1}`, x]));
console.log(result);A solution that uses Array.prototype.reduce and ECMAScript 2015:
const arr = [true, 6, 'wow', 'you are smart, bro'];
const result = arr.reduce((acc, cur, i) => ({ ...acc, [(`field${i + 1}`)]: cur }), {});
console.log(result);And a solution that uses Array.prototype.reduce and ECMAScript 5 (browsers as old as IE11):
var arr = [true, 6, 'wow', 'you are smart, bro'];
var result = arr.reduce(function(acc, cur, i) {
acc['field' + (i + 1)] = cur;
return acc;
}, {});
console.log(result);const arr = [true,1,'wow','you are smart, bro']
const f = (acc, rec, index) => {
acc[`field${index + 1}`] = rec //
return acc
}
const result = arr.reduce(f, {})
console.log(result)I extracted the callback function into f variable for readability's sake.
The callback function expects the following input: accumulator acc to store the results in, the value of the current processed element rec, and index.
const f = (acc, rec, index) => {...}
The index is optional but we need to get array indexes anyway to use them in our resulting object's keys. We know that array's index count starts from 0 and not from 1, so we have to add + 1 to the count to get field1 key instead of field0.
I chose to use string interpolation to get the necessary result:
`field${index + 1}`
Then we assign the corresponding array element to the object under the key we've just constructed:
acc[`field${index + 1}`] = rec
The reduce function expects the following input: callback (function f ) and initial value, which here should be an empty object {}, since we need to have an object as result.
reduce(f, {})
Now we create new variable result which will be the output of the reduce function on each element of the array arr:
const result = arr.reduce(f, {})
const arr = [true,6,'wow','you are smart, bro']
const obj = arr.reduce(
(acc, rec, index) => ({ ...acc, [`field${index + 1}`]: rec }),
{}
)
console.log(obj) 
const result = [true,6,'wow','you are smart, bro']
.reduce((acc, rec, i) => ({...acc, [`field${i + 1}`]: rec}),{})
console.log(result)
const database = [true, 1, "wow", "you are smart, bro"];
const result = (arr) => arr.reduce(
(acc, rec, i) => ({
...acc,
[`field${i + 1}`]: rec
}),
{}
);
console.log(result(database));1 step:
acc(0 elements) + field{0+1}: true
|
accumulator is empty
2 step:
acc(1 element) + field{1+1}: 1
|
field1: true
3 step:
acc(2 elements) + field{2+1}: "wow"
|
field1: true
field2: 1
4 step:
acc(3 elements) + field{3+1}: "you are smart, bro"
|
field1: true
field2: 1
field3: "wow"
end:
field1: true
field2: 1
field3: "wow"
field4: "you are smart, bro"
