Develop Reference

How to add label to js array?

Hi I am looking to create an array that looks similar to this
const userList = {
123: "Tom",
124: "Michael",
125: "Christin",
};
it contains both value and label, what I tried so far
let raw = []
for (let x in data) {
raw.push(data[x].facility_name : data[x].id)
}
but it didn't work because "," was expected, if someone can help please

You are confusing arrays and objects. You need to add a key to an object not push. I kept it as a for in loop, but a for of loop would make more sense.
const data = [
{ id: 1, facility_name: "foo1" },
{ id: 2, facility_name: "foo2" },
{ id: 3, facility_name: "foo3" }
];
let raw = {};
for (let x in data) {
raw[data[x].id] = data[x].facility_name;
}
console.log(raw);
How I would code it using reduce.
var data = [
{ id: 1, facility_name: "foo1" },
{ id: 2, facility_name: "foo2" },
{ id: 3, facility_name: "foo3" }
];
const raw = data.reduce(function (acc, facility) {
acc[facility.id] = facility.facility_name;
return acc;
}, {})
console.log(raw);

IF your data has nested objects then you might do this:
let raw = {};
for(x in data)
{
raw[data[x].facility_name] = data[x].id;
}
This is useful when you want to get rid of duplicates.

Logic to Transform data

I have an api that return me data in following format:
[
{
"_id": 1567362600000,
"KIDate": "2019-09-02",
"KITools": [
{
"data": 1,
"tool": "A"
},
{
"data": 2,
"tool": "B"
}
]
},
{
"_id": 1567519839316,
"KIDate": "2019-09-01",
"KITools": [
{
"data": 2,
"tool": "A"
},
{
"data": 1,
"tool": "C"
}
]
},
{
"_id": 1567519839317,
"KIDate": "2019-08-31",
"KITools": [
{
"data": 0,
"tool": "C"
}
]
},
]
I want to transform this data to get the following arrays:
Result 1 - [“2019-09-02”,”2019-09-01”,”2019-08-31”]
Result 2 - [ {name: ‘A’, data:[1, 2, 0] }, { name: 'B', data: [2, 0, 0] }, { name: 'C', data: [0, 1, 0]}]
Currently I am able to achieve this by using loops and per-defining variables with the tool name like following and looping the api data to push into this variable.
var result2 = [{
name: 'A',
data: []
}, {
name: 'B',
data: []
}, {
name: 'C',
data: []
}];
But this is not the expected behavior, the tool names can change and I have to figure that out dynamically based on the data returned by the api.
What is the best way to achieve this without looping like crazy.

You could use reduce method to get the result with array of dates and object of values for each tool.
const data = [{"_id":1567362600000,"KIDate":"2019-09-02","KITools":[{"data":1,"tool":"A"},{"data":2,"tool":"B"}]},{"_id":1567519839316,"KIDate":"2019-09-01","KITools":[{"data":2,"tool":"A"},{"data":1,"tool":"C"}]},{"_id":1567519839317,"KIDate":"2019-08-31","KITools":[{"data":0,"tool":"C"}]}]
const result = data.reduce((r, {KIDate, KITools}, i) => {
r.dates.push(KIDate);
KITools.forEach(({data: dt, tool}) => {
if(!r.values[tool]) r.values[tool] = Array(data.length).fill(0);
r.values[tool][i] = dt
})
return r;
}, {dates: [], values: {}})
console.log(result)

You can use reduce and forEach with Set and Map
Initialize accumulator as object with dates and data key, dates is a Set and data is Map
For every element add the KIDate to dates key,
Loop over KITools, check if that particular too exists in data Map if it exists update it's value by adding current values to id, if not set it's value as per current values
let data = [{"_id": 1567362600000,"KIDate": "2019-09-02","KITools": [{"data": 1,"tool": "A"},{"data": 2,"tool": "B"}]},{"_id": 1567519839316,"KIDate": "2019-09-01","KITools": [{"data": 2,"tool": "A"},{"data": 1,"tool": "C"}]},{"_id": 1567519839317,"KIDate": "2019-08-31","KITools": [{"data": 0,"tool": "C"}]},]
let final = data.reduce((op,{KIDate,KITools})=>{
op.dates.add(KIDate)
KITools.forEach(({data,tool})=>{
if(op.data.has(data)){
op.data.get(data).data.push(tool)
} else{
op.data.set(data, {name: data, data:[tool]})
}
})
return op
},{dates:new Set(),data: new Map()})
console.log([...final.dates.values()])
console.log([...final.data.values()])

The result1 array can be obtained via a direct .map(). To build the result2 array will require additional work - one approach would be to do so via .reduce() as detailed below:
const data=[{"_id":1567362600000,"KIDate":"2019-09-02","KITools":[{"data":1,"tool":"A"},{"data":2,"tool":"B"}]},{"_id":1567519839316,"KIDate":"2019-09-01","KITools":[{"data":2,"tool":"A"},{"data":1,"tool":"C"}]},{"_id":1567519839317,"KIDate":"2019-08-31","KITools":[{"data":0,"tool":"C"}]}];
const result1 = data.map(item => item.KIDate);
const result2 = data.reduce((result, item) => {
item.KITools.forEach(kitool => {
/* For current item, search for matching tool on name/tool fields */
let foundTool = result.find(i => i.name === kitool.tool);
if (foundTool) {
/* Add data to data sub array if match found */
foundTool.data.push(kitool.data);
} else {
/* Add new tool if no match found and init name and data array */
result.push({
name: kitool.tool,
data: [kitool.data]
});
}
});
return result;
}, []).map((item, i, arr) => {
/* Second phase of processing here to pad the data arrays with 0 values
if needed */
for (let i = item.data.length; i < arr.length; i++) {
item.data.push(0);
}
return item;
});
console.log('result1:', result1);
console.log('result2:', result2);

Finding objects in a nested array along with their position

I've taken the following sample from a different question. And I am able to identify the object. But I also need to find our the position of that object. For example:
var arr = [{
Id: 1,
Categories: [{
Id: 1
},
{
Id: 2
},
]
},
{
Id: 2,
Categories: [{
Id: 100
},
{
Id: 200
},
]
}
]
If I want to find the object by the Id of the Categories, I can use the following:
var matches = [];
var needle = 100; // what to look for
arr.forEach(function(e) {
matches = matches.concat(e.Categories.filter(function(c) {
return (c.Id === needle);
}));
});
However, I also need to know the position of the object in the array. For example, if we are looking for object with Id = 100, then the above code will find the object, but how do I find that it's the second object in the main array, and the first object in the Categories array?
Thanks!

Well, if every object is unique (only in one of the categories), you can simply iterate over everything.
var arr = [{
Id: 1,
Categories: [{Id: 1},{Id: 2}]
},
{
Id: 2,
Categories: [{Id: 100},{Id: 200}]
}
];
var needle = 100;
var i = 0;
var j = 0;
arr.forEach(function(c) {
c.Categories.forEach(function(e) {
if(e.Id === needle) {
console.log("Entry is in position " + i + " of the categories and in position " + j + " in its category.");
}
j++;
});
j = 0;
i++;
});

function findInArray(needle /*object*/, haystack /*array of object*/){
let out = [];
for(let i = 0; i < haystack.lenght; i++) {
if(haystack[i].property == needle.property) {
out = {pos: i, obj: haystack[i]};
}
}
return out;
}
if you need the position and have to filter over an property of the object you can use a simple for loop. in this sample your result is an array of new object because there can be more mathches than 1 on the value of the property.
i hope it helps

Iterate over the array and set index in object where match found
var categoryGroups = [{
Id : 1,
Categories : [{
Id : 1
}, {
Id : 2
},
]
}, {
Id : 2,
Categories : [{
Id : 100
}, {
Id : 200
},
]
}
]
var filterVal = [];
var needle = 100;
for (var i = 0; i < categoryGroups.length; i++) {
var subCategory = categoryGroups[i]['Categories'];
for (var j = 0; j < subCategory.length; j++) {
if (subCategory[j]['Id'] == findId) {
filterVal.push({
catIndex : i,
subCatIndex : j,
id : needle
});
}
}
}
console.log(filterVal);

Here is solution using reduce:
var arr = [{ Id: 1, Categories: [{ Id: 1 }, { Id: 2 }, ] }, { Id: 2, Categories: [{ Id: 100 }, { Id: 200 }, ] } ]
const findPositions = (id) => arr.reduce((r,c,i) => {
let indx = c.Categories.findIndex(({Id}) => Id == id)
return indx >=0 ? {mainIndex: i, categoryIndex: indx} : r
}, {})
console.log(findPositions(100)) // {mainIndex: 1, categoryIndex: 0}
console.log(findPositions(1)) // {mainIndex: 0, categoryIndex: 0}
console.log(findPositions(200)) // {mainIndex: 1, categoryIndex: 1}
console.log(findPositions(0)) // {}

Beside the given answers with fixt depth searh, you could take an recursive approach by checking the Categories property for nested structures.
function getPath(array, target) {
var path;
array.some(({ Id, Categories = [] }) => {
var temp;
if (Id === target) {
path = [Id];
return true;
}
temp = getPath(Categories, target);
if (temp) {
path = [Id, ...temp];
return true;
}
});
return path;
}
var array = [{ Id: 1, Categories: [{ Id: 1 }, { Id: 2 },] }, { Id: 2, Categories: [{ Id: 100 }, { Id: 200 }] }];
console.log(getPath(array, 100));
.as-console-wrapper { max-height: 100% !important; top: 0; }

How to get one json object format from another JSON format

Maybe this question has already been asked and answered somewhere but after searching for more than 3 hrs I'm asking this question.
Below is my JSON data
var my_data = [
{
"TempRture_qc": 4,
"VoltAGE": 44.09722,
"TempRture": 22.32,
"VoltAGE_qc": 55,
"_time": "2018-08-07T03:39:29.001Z"
},
{
"TempRture_qc": 2,
"VoltAGE": 42.09722,
"TempRture": 22.12,
"VoltAGE_qc": 0,
"_time": "2018-08-07T03:39:30.006Z"
},
{
"TempRture_qc": 1,
"VoltAGE": 43.09722,
"TempRture": 22.82,
"VoltAGE_qc": 0,
"_time": "2018-08-07T03:39:31.009Z"
}
];
desired output i need
[
{
"name": "TempRture_qc",
"data": [
{"name":"2018-08-07T03:39:29.001Z","y":4},
{"name":"2018-08-07T03:39:30.006Z","y":2},
{"name":"2018-08-07T03:39:33.017Z","y":1}
]
},
{
"name": "VoltAGE",
"data": [
{"name":"2018-08-07T03:39:29.001Z","y":44.09722},
{"name":"2018-08-07T03:39:30.006Z","y":42.09722},
{"name":"2018-08-07T03:39:33.017Z","y":43.09722}
]
},
{
"name": "TempRture",
"data": [
{"name":"2018-08-07T03:39:29.001Z","y":22.32},
{"name":"2018-08-07T03:39:30.006Z","y":22.12},
{"name":"2018-08-07T03:39:33.017Z","y":22.82}
]
},
{
"name": "VoltAGE_qc",
"data": [
{"name":"2018-08-07T03:39:29.001Z","y":55},
{"name":"2018-08-07T03:39:30.006Z","y":0},
{"name":"2018-08-07T03:39:33.017Z","y":0}
]
}
]
for getting this above output i have tried below code.
var accounting = [];
var fieldName = {};
for (var x in obj){
var mykey = Object.keys(obj[x]);
for (var mk in mykey){
if(mykey[mk]=='VoltAGE'){
fieldName.name = mykey[mk];
// accounting.push({
// "name":mykey[mk]
// })
}
if(mykey[mk]=='TempRture'){
fieldName.name = mykey[mk];
}
// console.log(mykey[mk]); //to get the key name
}
accounting.push({
"name" : obj[x]._time,
"y" : obj[x][employees.name],
})
fieldName.data = accounting;
}
console.log(fieldName );
by doing this what I'm getting is below JSON
{ name: 'TempRture',
data:
[ { name: '2018-08-07T03:39:29.001Z', y: 22.32 },
{ name: '2018-08-07T03:39:32.014Z', y: 22.12 },
{ name: '2018-08-07T03:39:33.017Z', y: 22.82 } ] }
I'm not able to understand how I will get the data in one JSON object.

For a solution with low time complexity, try .reduceing into an object indexed by keys of the inner object, creating a { name, data: [] } at that key in the accumulator if it doesn't exist there yet. Then, push to the data array, and get the values of the whole object:
var my_data=[{"TempRture_qc":4,"VoltAGE":44.09722,"TempRture":22.32,"VoltAGE_qc":55,"_time":"2018-08-07T03:39:29.001Z"},{"TempRture_qc":2,"VoltAGE":42.09722,"TempRture":22.12,"VoltAGE_qc":0,"_time":"2018-08-07T03:39:30.006Z"},{"TempRture_qc":1,"VoltAGE":43.09722,"TempRture":22.82,"VoltAGE_qc":0,"_time":"2018-08-07T03:39:31.009Z"}]
console.log(Object.values(
my_data.reduce((a, { _time, ...obj }) => {
Object.entries(obj).forEach(([name, val]) => {
if (!a[name]) a[name] = { name, data: [] };
a[name].data.push({ name: _time, y: val });
});
return a;
}, {})
));

var my_data=[{"TempRture_qc":4,"VoltAGE":44.09722,"TempRture":22.32,"VoltAGE_qc":55,"_time":"2018-08-07T03:39:29.001Z"},{"TempRture_qc":2,"VoltAGE":42.09722,"TempRture":22.12,"VoltAGE_qc":0,"_time":"2018-08-07T03:39:30.006Z"},{"TempRture_qc":1,"VoltAGE":43.09722,"TempRture":22.82,"VoltAGE_qc":0,"_time":"2018-08-07T03:39:31.009Z"}]
var keys = Object.keys(my_data[0])
var result= [];
for(i = 0; i<keys.length-1; i++) {
var obj = {name: keys[i],data: []}
obj.data = my_data.map(val=>({name: val["_time"], y: val[keys[i]]}));
result.push(obj);
}
console.log(result)

An understandable answer with map, findIndex and forEach functions will be
var my_data = [{ "TempRture_qc": 4, "VoltAGE": 44.09722, "TempRture": 22.32, "VoltAGE_qc": 55, "_time": "2018-08-07T03:39:29.001Z" }, { "TempRture_qc": 2, "VoltAGE": 42.09722, "TempRture": 22.12, "VoltAGE_qc": 0, "_time": "2018-08-07T03:39:30.006Z" }, { "TempRture_qc": 1, "VoltAGE": 43.09722, "TempRture": 22.82, "VoltAGE_qc": 0, "_time": "2018-08-07T03:39:31.009Z" } ],
result = [];
my_data.map(itm => {
let keys = Object.keys(itm);
keys.forEach(iitt => {
if (iitt != '_time') {
let index = result.findIndex(ii => {
return ii.name == iitt;
})
if (index == -1) {
result.push({
name: iitt,
data: []
});
result[result.length - 1].data.push({
name: itm["_time"],
y: itm[iitt]
})
} else {
result[index].data.push({
name: itm["_time"],
y: itm[iitt]
});
}
}
})
})
console.log(result)

node.js + Object Array

In my node app i have to construct an object array from another object array.
Consider my object array as..
[ { id_0: 356, id_1: 33, name_1: 'aaaa' },
{ id_0: 756, id_1: 89, name_1: 'bbbbb' },
{ id_0: 456, id_1: 89, name_1: 'ccccc' },
{ id_0: 356, id_1: 27, name_1: 'dddd' } ]
I have to construct an object array as like below:
[{
"356":["33":"aaaa","27":"ddddd"],------------->Changes made
"456":[{"89":"cccc"}],
"756":[{"89":"bbbbbbbb"}]
}]
I tried using async.map.But i cant get the right way to do it.Please help me to solve this.Thanks in advance...

You can use Array.prototype.reduce function, like this
console.log(data.reduce(function(result, current) {
var obj = {};
result[current.id_0] = result[current.id_0] || [];
obj[current.id_1] = current.name_1;
result[current.id_0].push(obj);
return result
}, {}));
Output
{ '356': [ { '33': 'aaaa' }, { '27': 'dddd' } ],
'456': [ { '89': 'ccccc' } ],
'756': [ { '89': 'bbbbb' } ] }
If you want to convert this to an array of object, just wrap the result of data.reduce with [] like this
console.log([data.reduce(function(result, current) {
...
...
}, {})]);
Edit:
result[current.id_0] = result[current.id_0] || [];
this line makes sure that result[current.id_0] is an array. If the value of result[current.id_0] is truthy, then that value is rturned but if it is not, then [] will be returned. So, a new array will be created and assigned to result[current.id_0]. It is actually a shorthand for
if (result.hasOwnProperty(current.id_0) === false) {
result[current.id_0] = [];
}
Edit 2: If you like to keep the grouped elements as an object, you could do like this
console.log(data.reduce(function(result, current) {
result[current.id_0] = result[current.id_0] || {};
result[current.id_0][current.id_1] = current.name_1;
return result
}, {}));
Output
{ '356': { '27': 'dddd', '33': 'aaaa' },
'456': { '89': 'ccccc' },
'756': { '89': 'bbbbb' } }