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JS reduceRight is causing arrays to become objects, how can I fix the logic?

I have an json object:
json = {
"array": [80, 50]
}
A third party jsoneditor, returns a path variable as a list of strings or index to the value. I use event listeners to detect changes to the value and I store those changes in a separate object to later submit to a form.
For example, if I change 50 to 60, this is what is returned:
node.path = ["array", 1]
node.value = 60
I am using reduceRight() to normally map the changes to the object to the changed object, however when the value is an Array it is converting the array to an object.
let delta = node.path.reduceRight((obj, elem) => ({[elem]: obj}), node.value)
//returns
delta = {array: {1: 60}}
//instead of
delta = {array: [80, 60]}
How can I check the original json and if the field is an Array object, don't reduce this into an object but keep the original Array and update the Array with the changed value within the Array? I need to submit the entire array into the form.
EDIT:
I know that I can do some custom logic within the reduce to check the original json and get the unchanged part of the array. I just dont know how to achieve that
let delta = node.path.reduceRight( function (obj, elem) {
//some logic here to account for arrays and get original array list and change only slected index
else {
return {[elem]: obj}), node.value
}
});
EDIT:
Alternatively, how can can I get the nested keys from the node.path and find the original array and then just update the array index? The path can sometimes be nested sothe path is always going to be the Array-like structure.
//this does not work
let orig_key_val = json[node.path]
Thanks!

This seems to work, finally... I used a regular reduce() and check if the key is an Array if it is store my original Array into a tmp object and save that key. The next time the reduce() comes around, if the index is on the last path element then set the tmp[tmp_key][key] to my target value and return the adjusted for Array object instead.
I can see how this will not work for nested json objects but for now I dont have any... Unless someone can show me how to figure that one out this is my implementation for now.
let tmp = {};
let tmp_key;
let delta = node.path.reduce((val, key, index, array) => {
if (Array.isArray(json[key])) {
tmp[key] = json[key]
tmp_key = key;
} else if (Object.keys(tmp).length !== 0 && index === node.path.length-1) {
tmp[tmp_key][key] = node.value;
return tmp
} else
return {[key]: val}
}, node.value);

How to modify an array of array, depending if an element in it matches an element from another array of array?

I have 2 set of array of arrays in Google Spreadsheet as follows:-
var arrayInput = [[ASIAPLY, "9/10/2020"], [PCCS, "9/10/2020"], [SCGM, "9/10/2020"]]
var arrayOuput = [[PCCS, "8/10/2020"]]
I want to insert the 2nd index of an element/array in the arrayInput if the 1st index is present in the outputArray. If it is not, I would like to add the whole element/array into outputArray. My desired outcome would look like this
var arrayOuput = [[PCCS, "9/10/2020", "8/10/2020"], [ASIAPLY, "9/10/2020"], [SCGM, "9/10/2020"]]
I have tried this
function testData() {
// get the range of input data
var arrayInput = wlSheet.getRange(2, 2, 3, 2).getValues();
// get the range of output counter
var arrayOuput = wlSheet.getRange(2, 7, 1, 2).getValues();
arrayOuput.find((outputRow, i, arr) => {
arrayInput.map((r, index, array) => {
if (r[0] !== outputRow[0]) {
return wlSheet.getRange(arr.length + 2 + index, 7, 1, 2).setValues([[counter, hyperlinkText]]);
} else {
return wlSheet.getRange(i + 2, 8).insertCells(SpreadsheetApp.Dimension.COLUMNS).setValue(hyperlinkText);
}
});
});
}
However the code above has resulted into [[PCCS, "9/10/2020", "8/10/2020"], [PCCS, "9/10/2020"], [ASIAPLY, "9/10/2020"], [SCGM, "9/10/2020"]]; instead of desired result.
Is there a way of achieving what I intended to do in Google Apps Script?
Thanks in advance.

If you want to insert an item, you can't use Array.prototype.map as it will return a new array.
Now i'm not familiar with google apps scripts, or interacting with spreadsheets, but the basic JS would look like this:
What you are trying can be easily done with a for...of-loop
The basic steps are:
we have two arrays in the shape of a key followed by a number of values
if your familiar with TypeScript types: [key: Key, ...values: string[]]
we want to take from input to output
for each element in input
if output has an element with the corresponding key: append own values to it
else add self to output
const inArr = [['ASIAPLY', '9/10/2020'], ['PCCS', '9/10/2020'], ['SCGM', '9/10/2020']]
const outArr = [['PCCS', '8/10/2020']]
// iterate over the array elements and use destructuring to
// extract the key form the other values
for (const [key, ...values] of arrayInput) {
// look for an element in `output` that has that key
const target = outArr.find(([ky, value]) => ky === key)
// if we found one, push the values to it
if (target) target.push(...values)
// else push your key-values onto the output array
else outArr.push([key, ...values])
}
The result using the example arrays is:
[
[ 'PCCS', '8/10/2020', '9/10/2020' ],
[ 'ASIAPLY', '9/10/2020' ],
[ 'SCGM', '9/10/2020' ]
]
Since we used spread syntax (...values) in the destructuring, this is little iterator is able to handel 0 or more values by default and will always output the approptiate result.
This should solve this problem in an elegant manner and it is easyly modifiable if needed.

Create a new output array using Map and Array.map:
/*<ignore>*/console.config({maximize:true,timeStamps:false,autoScroll:false});/*</ignore>*/
const array1 = [
['ASIAPLY', '9/10/2020'],
['PCCS', '9/10/2020'],
['SCGM', '9/10/2020'],
],
array2 = [['PCCS', '8/10/2020']],
array2Map = new Map(array2),
arrayOutput = array1.map(([k, v]) => [k, v, array2Map.get(k)]);
console.log(arrayOutput);
<!-- https://meta.stackoverflow.com/a/375985/ --> <script src="https://gh-canon.github.io/stack-snippet-console/console.min.js"></script>
To use setValues, the arrays must be of uniform size.

how to get the last 3 elements with specific name value with JMESPATH and javascript?

I have the below json data array:
[{"name":"Button1","date":"1596959802144"},{"name":"Button2","date":"1596959804238"},{"name":"Button3","date":"1596959809334"},{"name":"Button1","date":"1597000878135"},{"name":"Button2","date":"1597000896335"},{"name":"Button3","date":"1597000901536"},{"name":"Button2","date":"1597000904437"},{"name":"Button3","date":"1597000909535"},{"name":"Button1","date":"1597000912250"},{"name":"Button2","date":"1597000939937"},{"name":"Button3","date":"1597000957940"},{"name":"Button2","date":"1597000964640"},{"name":"Button1","date":"1597001005141"},{"name":"Button2","date":"1597001010240"},{"name":"Button3","date":"1597001014845"},{"name":"Button2","date":"1597001021644"},{"name":"Button1","date":"1597001025738"},{"name":"Button2","date":"1597001049030"},{"name":"Button3","date":"1597001054139"},{"name":"Button1","date":"1597001057741"},{"name":"Button2","date":"1597001060340"},{"name":"Button3","date":"1597001062445"},{"name":"Button1","date":"1597002599045"},{"name":"Button1","date":"1597002604128"},{"name":"Button1","date":"1597002609546"},{"name":"Button1","date":"1597002613435"},{"name":"Button1","date":"1597002681736"},{"name":"Button1","date":"1597002690843"},{"name":"Button1","date":"1597002694136"},{"name":"Button1","date":"1597002696349"},{"name":"Button1","date":"1597002699243"}]
and I would like to use JMESPath javascript library to get only the last 3 entries per each distinct name value. For example:
[{"name":"Button3","date":"1597001014845"},{"name":"Button2","date":"1597001021644"},{"name":"Button2","date":"1597001049030"},{"name":"Button3","date":"1597001054139"},{"name":"Button2","date":"1597001060340"},{"name":"Button3","date":"1597001062445"},{"name":"Button1","date":"1597002694136"},{"name":"Button1","date":"1597002696349"},{"name":"Button1","date":"1597002699243"}]
So the last 3 occurrences fro each name = Button*
checking on stackOverflow and I saw that with JQ is possible to do using this function: map_values(delpaths(keys_unsorted[:-2] | map([.])))
Get last N elements for each item of a JSON object
Is there any way to do? or using other javascript module?

If you don't care about the order in your resulting array, here would be a pure JavaScript way to do this:
const getLastNForEveryName = (arr, n) => {
const lastNOfEach = arr.reduce((acc, curr) => {
if(acc[curr.name] == null) { // If the key doesnt exist yet, create it with the current item in the array
acc[curr.name] = [curr];
} else {
if(acc[curr.name].length >= n) // If the array is as big as the desired size alread, remove the first added one
acc[curr.name].shift();
acc[curr.name].push(curr); // push the current item in the array
}
return acc;
}, {})
return Object.values(lastNOfEach).flatMap(l => l); // Just get the values of the object and flatMap it, so that we dont have arrays of arrays
}
// Testing
const values = [{"name":"Button1","date":"1596959802144"},{"name":"Button2","date":"1596959804238"},{"name":"Button3","date":"1596959809334"},{"name":"Button1","date":"1597000878135"},{"name":"Button2","date":"1597000896335"},{"name":"Button3","date":"1597000901536"},{"name":"Button2","date":"1597000904437"},{"name":"Button3","date":"1597000909535"},{"name":"Button1","date":"1597000912250"},{"name":"Button2","date":"1597000939937"},{"name":"Button3","date":"1597000957940"},{"name":"Button2","date":"1597000964640"},{"name":"Button1","date":"1597001005141"},{"name":"Button2","date":"1597001010240"},{"name":"Button3","date":"1597001014845"},{"name":"Button2","date":"1597001021644"},{"name":"Button1","date":"1597001025738"},{"name":"Button2","date":"1597001049030"},{"name":"Button3","date":"1597001054139"},{"name":"Button1","date":"1597001057741"},{"name":"Button2","date":"1597001060340"},{"name":"Button3","date":"1597001062445"},{"name":"Button1","date":"1597002599045"},{"name":"Button1","date":"1597002604128"},{"name":"Button1","date":"1597002609546"},{"name":"Button1","date":"1597002613435"},{"name":"Button1","date":"1597002681736"},{"name":"Button1","date":"1597002690843"},{"name":"Button1","date":"1597002694136"},{"name":"Button1","date":"1597002696349"},{"name":"Button1","date":"1597002699243"}];
console.log(getLastNForEveryName(values, 3));

Retrieving values for each key in JS Object and pushing each set of values for each key to it's own array

I want to iterate through my key/value pairs and push all the values for each key into its own array. These arrays of values of each key should be pushed to a single output array.
I hope this explains what I'm trying to do:
Input: map = {"hi":["hello","hey","howdy"],"bye":["Goodbye","Ciao"]}
Output: output = [["hello","hey","howdy"],["Goodbye","Ciao"]]
This is what I have so far:
return Object.keys(map).reduce((output, key) => {
return output.push(map[key])
},[])
Any help on iterating through the values for each key and adding those values to an array within another output array would be greatly appreciated.
For background, this is part of a grouping anagrams problem so I'm populating my Map as follows from a provided array "str" of strings.
let map = {};
str.forEach(anagram => {
const sortedWord = anagram
.split("")
.sort()
.join("");
map[sortedWord] = map[sortedWord] || [];
map[sortedWord].push(anagram);
});

All you need is the built-in Object.values():
Object.values() returns an array whose elements are the enumerable property values found on the object.
const map = {"hi":["hello","hey","howdy"],"bye":["Goodbye","Ciao"]};
const output = Object.values(map);
console.log(output);

Using reduce the return pushs to 'output' no need to push yourself:
return Object.keys(map).reduce((output, key) => {
return map[key]
},[])
You could also use map:
return Object.keys(map).map((key) => {
return map[key]
})

Apart from the above two excellent answers, you may choose to use Object.entries(), which will return an array from the input object's [key, value] pair. From there, we can return only the value into the resulting array, giving you the expected result.
const input = {"hi":["hello","hey","howdy"],"bye":["Goodbye","Ciao"]}
const result = Object.entries(input).map(item => item[1]);
console.log(result);
However, do take note that Object.entries() is not supported by Internet Explorer browsers.
Alternatively, you may use the good old for..in statement to iterate through the enumerable properties of the object, followed by pushing the corresponding values to the resulting array.
const input = {"hi":["hello","hey","howdy"],"bye":["Goodbye","Ciao"]}
const result = []
for (const property in input) {
result.push(input[property]);
}
console.log(result);

Javascript map through array to make another array of objects

I want to go through an array of strings, and depending on what the string is, make an array of objects.
For example, if the array is:
[a,a,a,b,b,c,d]
I want to map through the array and make an object with key and value pairs that add up the strings consecutively:
[{a:1},{a:2},{a:3},{b:1},{b:2},{c:1},{d:1}]
How do I do this?
I've tried mapping through, but I can't get how to add on to the previous object's value (a:1 -> a:2)

While mapping, you need to store a separate count of how many times each item has appeared, and increment the appropriate key each iteration. You might use a Map for this:
const input = ['a','a','a','b','b','c','d'];
const map = new Map();
console.log(
input.map(char => {
const count = (map.get(char) || 0) + 1;
map.set(char, count);
return { [char]: count };
})
)