Develop Reference

push the total amount of objects to an array

I am trying to count how many times a specific item appears in an array. And then push that amount to an other array. I got the counter working, although when I push this amount to the array the type of this value turn out te be Not A Number...
Here is my code:
res2 =
0: (2) [29682885, "Jean-Paul"]
1: (2) [29682886, "DEMO Martin"]
2: (2) [29682887, "Johan"]
3: (2) [29682892, "Peter"]
4: (2) [29682900, "Antoine"]
5: (2) [29682902, "Sandra"]
6: (2) [29682906, "Kevin"]
7: (2) [29682910, "Wouter"]
8: (2) [29682911, "Tom"]
9: (2) [4, "Autotask"]
res3 =
0: (2) [29682885, "2019-05-16T08:25:32Z"]
1: (2) [29682885, "2019-07-01T13:11:00Z"]
2: (2) [29682885, "2019-07-03T10:21:07Z"]
3: (2) [29682885, "2019-09-03T14:00:45Z"]
4: (2) [29682885, "2019-09-11T09:59:07Z"]
5: (2) [29682885, "2019-09-17T14:13:39Z"]
6: (2) [29682885, "2019-10-09T16:48:41Z"]
7: (2) [29682885, "2019-10-30T13:48:12Z"]
8: (2) [29682885, "2019-10-30T14:13:01Z"]
9: (2) [29682885, "2019-10-30T14:34:13Z"]
10: (2) [29682885, "2019-11-07T13:41:27Z"]
11: (2) [29682885, "2019-11-22T12:41:08Z"]
...
res2.sort();
res3.sort();
res3.forEach(sale => {
res2.forEach(person => {
if (sale[0] === person[0]) {
if (person[1] === undefined) {
person[1] = 1;
console.log(person[1]);
} else {
person[1].occurrences++;
console.log(person[1]);
prepArray.push(person[1]);
}
prepArray.push(person[1]);
}
});
});
prepArray.push(person[1]); retruns an NaN somehow. But the console shows the exact amount I would like to push to my prepArray...

I've used a mix of filter, flat, map to achieve this. Added code comments to explain what logic is being used.
res2 = [[29682885, "Jean-Paul"],
[29682886, "DEMO Martin"],
[29682887, "Johan"],
[29682892, "Peter"],
[29682900, "Antoine"],
[29682902, "Sandra"],
[29682906, "Kevin"],
[29682910, "Wouter"],
[29682911, "Tom"],
[4, "Autotask"]]
res3 = [[29682885, "2019-05-16T08:25:32Z"],
[29682885, "2019-07-01T13:11:00Z"],
[29682902, "2019-07-03T10:21:07Z"],
[29682885, "2019-09-03T14:00:45Z"],
[29682885, "2019-09-11T09:59:07Z"],
[29682885, "2019-09-17T14:13:39Z"],
[29682902, "2019-10-09T16:48:41Z"],
[4, "2019-10-30T13:48:12Z"],
[4, "2019-10-30T14:13:01Z"],
[29682911, "2019-10-30T14:34:13Z"],
[29682911, "2019-11-07T13:41:27Z"],
[29682911, "2019-11-22T12:41:08Z"]];
// pick only the ids from res3
// this makes it easier for comparison
let res = res3.map(v => {
return v.shift();
}).flat()
let final = [];
// loop over res2, and count occurrences using .filter().length
res2.map(sale => final.push([sale[1], res.filter(person => person === sale[0]).length]));
console.log(final);
// if you want the output as an object,
// you can do the following
let finalObj = {};
res2.map(sale => finalObj[sale[1]] = res.filter(person => person === sale[0]).length);
console.log({ finalObj })
I've modified the input set (res3) slightly to show the difference in counts, the above code outputs the following,
[
[
"Jean-Paul",
5
],
[
"DEMO Martin",
0
],
[
"Johan",
0
],
[
"Peter",
0
],
[
"Antoine",
0
],
[
"Sandra",
2
],
[
"Kevin",
0
],
[
"Wouter",
0
],
[
"Tom",
3
],
[
"Autotask",
2
]
]
Edited my answer to get the desired output in object format, so now you'll get,
{
"Jean-Paul": 5,
"DEMO Martin": 0,
"Johan": 0,
"Peter": 0,
"Antoine": 0,
"Sandra": 2,
"Kevin": 0,
"Wouter": 0,
"Tom": 3,
"Autotask": 2
}

I don't understand many parts of your code, but trying to interpretate it:
res2 = [
[29682885, "Jean-Paul"],
[29682886, "DEMO Martin"],
[29682887, "Johan"],
[29682892, "Peter"],
[29682900, "Antoine"],
[29682902, "Sandra"],
[29682906, "Kevin"],
[29682910, "Wouter"],
[29682911, "Tom"],
[4, "Autotask"],
];
res3 = [
[29682911, "2019-05-16T08:25:32Z"],
[29682885, "2019-07-01T13:11:00Z"],
[29682902, "2019-07-03T10:21:07Z"],
[29682885, "2019-09-03T14:00:45Z"],
[29682885, "2019-09-11T09:59:07Z"],
[29682902, "2019-09-17T14:13:39Z"],
[29682885, "2019-10-09T16:48:41Z"],
[29682885, "2019-10-30T13:48:12Z"],
[29682885, "2019-10-30T14:13:01Z"],
[29682885, "2019-10-30T14:34:13Z"],
[29682911, "2019-11-07T13:41:27Z"],
[29682911, "2019-11-22T12:41:08Z"]
]
res2.sort();
res3.sort();
const prepArray = {};
res3.forEach(sale => {
res2.forEach(person => {
if (sale[0] === person[0]) {
if (person[1] === undefined) {
person[1] = 1;
}
prepArray[person[1]] = prepArray[person[1]] || 0;
prepArray[person[1]] += 1;
}
});
});
console.log(prepArray)

How to merge nested arrays into a new object?

I am struggeling a bit to merge nested arrays into a new object.
I have an array with nested objects in it. The objects contain an array. Now I want to merge the entries of this array into a new object and assign a value to it. For example "false". Please see the example.
Current Structure:
const arr = [
{
baa: "some",
foo: ["1", "2", "3"],
},
{
baa: "some",
foo: [
"4",
"5",
"6",
"7",
],
},
]
Target Structure: merge "foo" entries into object and assign value.
const obj = {
1: false,
2: false,
3: false,
4: false,
5: false,
6: false,
7: false,
};

Fetch the array foo and iterate over using forEach and get the value and make it a property, You can do this using reduce.
const arr = [
{
baa: "some",
foo: ["1", "2", "3"],
},
{
baa: "some",
foo: ["4", "5", "6", "7"],
},
];
const result = arr.reduce((acc, curr) => {
const { foo } = curr;
foo.forEach((el) => (acc[el] = false));
return acc;
}, {});
console.log(result);

More declarative answer:
const arr = [
{
baa: "some",
foo: ["1", "2", "3"],
},
{
baa: "some",
foo: ["4", "5", "6", "7"],
},
];
// Build `obj` from `arr`
const obj = Object.fromEntries(
arr.map(val => val.foo)
.flat()
.map(
key => [key, false]
)
)
console.log(obj)
Side note: not compatible with legacy browsers such as IE11, see coverage here: https://caniuse.com/mdn-javascript_builtins_object_fromentries

While the other answers are correct I find them so much harder to read than a simple double loop.
let result = {}
for(let obj of arr){
for(let innerArrElem of obj.foo){
result[innerArrElem] = false
}}
}}

function populate(arr, value) {
return arr.reduce((acc, element) => {
element.foo.forEach((f) => acc[f] = false);
return acc;
}, {})
}

How can I convert an indexed JavaScript object to an array of objects?

I have an object that looks like this:
obj = {
"price": {0: "10.00", 1: "15.00", 2: "6.00"},
"serialNumber": {0: 1000, 1: 2000, 2: 3000}
}
I'm trying to convert it into an array of objects so I can do obj.map((obj, idx)=>{//display obj.price and obj.serialNumber//}), so I want to convert obj into an array like this:
obj_array = [{"price":"10.00", "serialNumber": 1000}, {"price":"15.00", "serialNumber": 2000},{"price":"6.00", "serialNumber": 3000}]
I initially used array = Object.values(obj['serialNumber']) to just get serialNumber, but due to the way Object.values works, I can't just do array = Object.values(obj['serialNumber','price']) to get both. The values() function will ignore the serialNumber field and just make an array of prices. Any help would be appreciated!

You can use array#reduce with Object.entries() to convert your object to array.
const obj = { "price": { 0: "10.00", 1: "15.00", 2: "6.00" }, "serialNumber": { 0: 1000, 1: 2000, 2: 3000 } },
result = Object.entries(obj).reduce((r,[key, value]) => {
Object.values(value).forEach((val, i) => {
r[i] = {...(r[i] || {}), [key]: val};
});
return r;
},[]);
console.log(result);

riot js pushing index to a array

I woking in riot js and i have sorted the following abclist as following.
abclist = [];
abc = {year:year, name1:name1, order:order};
abclist.push(abc);
abclist.sort(function(a,b) {return (a.order > b.order) ? 1 : ((b.order > a.order) ? -1 : 0);} );
printing on console the abclist is like below.
0: {year: "2018", name1: "cc", order: "1"}
1: {year: "2018", name1: "jj", order: "2"}
I want to add these array index(0,1)to the array like below.
0: {index:0, year: "2018", name1: "cc", order: "1"}
1: {index:1, year: "2018", name1: "jj", order: "2"}
Please help me on this.

The question is not strictly related to riot.
An easy way to achieve that is to reiterate the array and add a field to each object like this:
for(var i = 0; i < abclist.length; i++){
abclist[i]['index'] = i;
}
You can see it in this fiddle: https://jsfiddle.net/7esmssup/6/

how to transform object with list of properties to array when Array.prototype.slice.call does not work?

This is working for list:
> Array.prototype.slice.call([1,2,3])
> [1, 2, 3]
How to create list from this type of data {1: "1", 2: "2", 3: "3"} ? Are there other methods than iterating object with for ?
the Array.prototype.slice.call() is not working here and gives []
This came from data = Object {0: Object, 1: Object, 2: Object, total : '29'} and then i delete data['total'] and need to access to slice, pop and other methods of Array

You could use the keys and map the values.
var o = {1: "1", 2: "2", 3: "3"},
a = Object.keys(o).map(function (k) {
return o[k];
});
console.log(a);
console.log(Array.prototype.slice.call({1: "1", 2: "2", 3: "3", length:5}));
The question arised, why Array.prototype.slice.call does not work. Basically because a length property is missing.
Only properties, which can be used as indices are used.
var o1 = {1: "1", 2: "2", 3: "3"},
o2 = {1: "1", 2: "2", 3: "3", length: 5},
o3 = {1: "1", 2: "2", 3: "3", abc: 42, length: 5},
o4 = {0: "0", 1: "1", 2: "2", 3: "3"};
o4.length=Object.keys(o4).length;
console.log(Array.prototype.slice.call(o1));
console.log(Array.prototype.slice.call(o2));
console.log(Array.prototype.slice.call(o3));
console.log(Array.prototype.slice.call(o4));
Note: Dynamic length of properties-in-object could be assigned using Object.keys(OBJECT). The cause of getting undefined in console is missing property at index 0

var list = [];
for (item in obj) {
list.push(obj[item]);
}
//use list.push(parseInt(obj[item])) for number array
You can also do the following if you want it straight
Object.values(obj);