Develop Reference

Fastest way to clean path collisions in array of strings

This is a hard one to explain, but here goes. I need to clean an array of 'path' strings where if a path has sub properties it not include the top level property. but only the child properties
E.g
[
'firstName',
'address',
'address.local.addressLine1',
'address.local.addressLine2',
'address.local',
]
Should become:
[
'firstName',
'address.local.addressLine1',
'address.local.addressLine2',
'address.local',
]
I have a fairly verbose function kind of working so far, but looking to see if there is a more elegant/better solution than this:
function cleanCollisions(array) {
var output = [];
// return [...new Set(array)];
var map = array.reduce(function(set, field) {
if (!Boolean(field)) {
return set;
}
////////////////
var rootKey = field.split('.')[0];
if(!set[rootKey]) {
set[rootKey] =[];
}
var count = field.split('.').length -1;
if(count) {
set[rootKey].push(field);
}
return set;
}, {})
for(const key in map) {
value = map[key];
if(value.length) {
output.push(value);
} else {
output.push(key);
}
}
////////////////
return output.flat();
}

I'd first iterate over the array to extract the top property of all strings that have sub properties, then filter out all those top properties.
const input = [
'firstName',
'address',
'address.local.addressLine1',
'address.local.addressLine2',
'address.local',
];
const topLevelProps = new Set();
for (const str of input) {
const match = str.match(/^(.*?)\./);
if (match) {
topLevelProps.add(match[1]);
}
}
const output = input.filter(str => !topLevelProps.has(str));
console.log(output);

A variation of the answer by CertainPerformance but using filter and map instead of regex:
const paths = [
'firstName',
'address',
'address.local.addressLine1',
'address.local.addressLine2',
'address.local',
];
const roots = paths.filter(p => p.includes('.')).map(p => p.split('.')[0]);
const cleansed = paths.filter(p => p.includes('.') || !roots.includes(p));
console.log(cleansed);

How to convert an array of objects into a single object using reduce?

I have the following array of object.
[
{ claimNumber1: 'R12345', checkNumber1: '' },
{ claimNumber2: 'T1234', checkNumber2: 'abcd' },
{ claimNumber3: 'Z4567', checkNumber3: 'qwer' }
]
Using reduce, I want to convert this to below.
{
claimNumber1:'R12345',
checkNumber1:'',
claimNumber2:'T1234',
checkNumber2:'',
claimNumber3:'Z4567',
checkNumber3:'',
}
I tried below but didn't get what I expected.
.reduce((obj, item) =>{
return {...obj,item}
} ,{});

You should spread the item object, because item is an object
const arr = [
{ claimNumber1: "R12345", checkNumber1: "" },
{ claimNumber2: "T1234", checkNumber2: "abcd" },
{ claimNumber3: "Z4567", checkNumber3: "qwer" },
];
const result = arr.reduce((obj, item, i) => {
return { ...obj, ...item, [`checkNumber${i + 1}`]: "" };
}, {});
console.log(result);

Almost there. You just need to spread the item as well.
.reduce((obj, item) => {
return {
...obj,
...item,
};
}, {});

I think you should spread every item in reducer.
Here is my code.
const res = arr.reduce((prev, item) => {
return { ...prev, ...item };
}, {});
And result is
{
claimNumber1: 'R12345',
checkNumber1: '',
claimNumber2: 'T1234',
checkNumber2: 'abcd',
claimNumber3: 'Z4567',
checkNumber3: 'qwer'
}

I'm not sure of the benefit of using reduce in this situation. A simple loop would be self-documenting, and easier to read.
const data = [
{ claimNumber1: 'R12345', checkNumber1: '' },
{ claimNumber2: 'T1234', checkNumber2: 'abcd' },
{ claimNumber3: 'Z4567', checkNumber3: 'qwer' }
];
const out = {};
// For every object in the array
for (const obj of data) {
// Get an array of its keys and iterate over them
for (const key of Object.keys(obj)) {
// If it's a claim add that value to the output
// object property, otherwise set that property value
// to an empty string.
if (key.startsWith('claim')) {
out[key] = obj[key];
} else {
out[key] = '';
}
}
}
console.log(out);
Additional documentation
Object.keys

How to dynamically add data from an array with objects to a nested array?

I have this set of data that I get dynamically -
This is the data I dynamically get
and my question is how can I get the values from the key, pattern and label and put them in a nested object like this - how should the nested object look like.
My current code is
let mergeTagsObj = {};
const merg = function(arr){
const propertyDataMap = arr.map(x => x.key);
propertyDataMap.forEach(x => {
mergeTagsObj[x] = {}
});
console.log(mergeTagsObj);
// console.log(object);
};
merg(displayArr)
displayArr has the data that I dynamically get, and I map each one to get the key so I can then give the object property a name. But after that I need to get the other 2 (pattern and label) and put it in the mergeTagsObj;
ex: mergeTagsObj = {
firstName:{
name:{label}
value:{pattern}
},
...
};

You can add the pattern and label in your forEach and any other logic that you might need to transform the data.
const data = [{key: 'firstName', pattern: "{{firstName}}", label: "First Name"},
{key: 'lastName', pattern: "{{lastName}}", label: "Last Name"},
{key: 'unsubscribeLink', pattern: "{{unsubscribeLink}}", label: "Unsubscribe Link"}
]
const transformDataToTagsObject = (dData) => {
const dynamicData = {};
dData.forEach((currentData, index) => {
const currentKey = currentData.key
const name = currentData.label
let value = currentData.pattern
if(currentData.key === 'unsubscribeLink'){
value = `<a href='${value}'>Unsubscribe</a>`
}
dynamicData[currentKey] = {
name,
value
}
})
const tagsObject = {
tags: dynamicData
}
return tagsObject;
}
const finalResults = transformDataToTagsObject(data)
console.log(finalResults)

Not most elegant solution, but I think this should work. Don't need to create the array of keys first you can just iterate over the arr of objects.
const merg = function(arr){
arr.forEach(x => {
mergeTagsObj[x.key] = {};
mergeTagsObj[x.key]['name'] = x.label;
mergeTagsObj[x.key]['value'] = x.pattern
});
console.log(mergeTagsObj);
// console.log(object);
};

// Given
const data = [
{key: "firstName", pattern: "{{firstName}}", label: "First Name"},
{key: "unsubscribeLink", pattern: "{{unsubscribeLink}}", label: "Unsubscribe Link"}
];
const tagsObject = data.reduce((obj, item) => {
const key = item.key;
const name = item.label;
let value = item.pattern;
if (key === 'unsubscribeLink') value = 'Unsubscribe';
return {...obj, [key]: {name, value}};
}, {});
console.log(tagsObject);

how to get array according to conditions in javascript

My array comes like this
var data=[{PRODUCT : P1}, {PRODUCT: P2}]
I wantt to convert this into [P1, P2].
Sometimes my array comes like this
var data=[{ITEM: I1, QUANTITY:1}, {ITEM: I2, QUANTITY:2}]
I wantt to convert this into [I1, I2].
so can we make a common function, where I just want to extract particular value of array and make a new array.
p.s. Thank you in advance
I tried to write the logic like this:
data.map((d, index) => { var result= [];
result.includes(d[0]); })
but it,s not dynamic

You could define a function which will always get the first value of the first object key, this should satisfy your needs based on the above
var data1 = [{
ITEM: 'I1',
QUANTITY: 1
}, {
ITEM: 'I2',
QUANTITY: 2
}]
var data2 = [{
PRODUCT: 'P1'
}, {
PRODUCT: ' P2'
}]
function getArrayOfValues(list) {
return list.reduce((acc, x) => {
const firstValue = Object.values(x)[0];
acc.push(firstValue)
return acc;
}, [])
}
const result1 = getArrayOfValues(data1)
console.log(result1)
const result2 = getArrayOfValues(data2)
console.log(result2)

function getProductOrItem(list) {
return list.reduce((accumulator, obj) => {
if (obj.PRODUCT) {
accumulator.push(obj.PRODUCT);
} else if (obj.ITEM) {
accumulator.push(obj.ITEM);
}
return accumulator;
}, [])
}

you can iterate through your array with map() method and inside it extract the value of a first entity of an object in your array and simply get a new array with all values:
const data1 =[{PRODUCT : 'P1'}, {PRODUCT: 'P2'}]
const data2 = [{ITEM: 'I1', QUANTITY: 1}, {ITEM: 'I2', QUANTITY: 2 }]
const transformValuesOfArray = (arrayToTransform) =>
arrayToTransform.map(value => {
const firstObjectValue = Object.values(value)[0]
return firstObjectValue
})
console.log(transformValuesOfArray(data1))
console.log(transformValuesOfArray(data2))

javascript find child object in nested arrays

I have a javascript structure like below (nested arrays of objects)
var categoryGroups = [
{
Id: 1, Categories: [
{ Id: 1 },
{ Id: 2 },
]
},
{
Id: 2, Categories: [
{ Id: 100 },
{ Id: 200 },
]
}
]
I want to find a child Category object matching an Id, assuming the Category Id's are all unique.
I've got this below, but was wondering if there is a more concise way of doing it:
var category, categoryGroup, found = false;
for (i = 0; i < categoryGroups.length ; i++) {
categoryGroup = categoryGroups[i];
for (j = 0; j < categoryGroup.Categories.length; j++) {
category = categoryGroup.Categories[j];
if (category.Id === id) {
found = true;
break;
}
}
if (found) break;
}

Using flatMap in ES2019
const category = categoryGroups.flatMap(cg => cg.Categories).find(c => c.Id === categoryId);

Caveat: This uses a couple of Array.prototype functions that were only added in ECMAScript 5 and thus will not work with older browsers unless you polyfill them.
You can loop over all first-level objects in your array, and then filter the categories based on your condition and collect all matches in an array. Your final result will be the first element in the array of matches (no match found if array is empty).
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);
}));
});
console.log(matches[0] || "Not found");
JSFiddle: http://jsfiddle.net/b7ktf/1/
References:
Array.prototype.forEach
Array.prototype.concat
Array.prototype.filter

Using only Array.prototype.filter():
If you are sure that the id you are looking for exists, you can do:
var id = 200; // surely it exists
var category = arr.filter(g => g.Categories.filter(c => c.Id === id)[0])[0].Categories.filter(c => c.Id === id)[0];
If you are not sure that it exists:
var id = 201; // maybe it doesn't exist
var categoryGroup = arr.filter(e => e.Categories.filter(c => c.Id === id)[0])[0];
var category = categoryGroup ? categoryGroup.Categories.filter(c => c.Id === id)[0] : null;
jsfiddle

Using reduce and recursion :
function nestedSearch(value) {
return categoryGroups.reduce(function f(acc, val) {
return (val.Id === value) ? val :
(val.Categories && val.Categories.length) ? val.Categories.reduce(f, acc) : acc;
});
}
> try on JSFiddle

check the code in the fiddle
var categoryGroups = [
{
Id: 1, Categories: [
{ Id: 1 },
{ Id: 2 },
]
},
{
Id: 2, Categories: [
{ Id: 100 },
{ Id: 200 },
]
}
]
var id = 100;
var x = 'not found';
var category, categoryGroup, found = false;
for (i = 0; i < categoryGroups.length ; i++) {
categoryGroup = categoryGroups[i];
for (j = 0; j < categoryGroup.Categories.length; j++) {
category = categoryGroup.Categories[j];
if (category.Id == id) {
var x = category.Id;
found = true;
break;
}
}
if (found) break;
}
alert(x);
The above code checks if id = 100 is found in the array. If found will alert the value else alerts that its not found. value '100' has been hardcoded for the sake of demo

You could wrap it inside a function to get rid of the awkward break; syntax and you can load each element into a variable inside the for(;;) construct to shave off a few lines.
function subCategoryExists(groups, id)
{
for (var i = 0, group; group = groups[i]; ++i) {
for (var k = 0, category; category = group.Categories[k]; ++k) {
if (category.Id == id) {
return true;
}
}
}
return false;
}
var found = subCategoryExists(categoryGroups, 100);

Easy way using lodash library of NodeJS (assuming you are using NodeJS):
const _ = require('lodash');
let category ;
let categoryGroup = _.find(categoryGroups, (element)=>{
category = _.find(element.Categories, {Id : 100});
return category;
});
console.log(categoryGroup); // The category group which has the sub category you are looking for
console.log(category); // The exact category you are looking for

If you want to actually return the inner category (instead of just checking for it's presence) you can use reduce:
return categoryGroups.reduce((prev, curr) => {
//for each group: if we already found the category, we return that. otherwise we try to find it within this group
return prev || curr.Categories.find(category => category.Id === id);
}, undefined);
This short-circuits on the inner categories, and touches each categoryGroup once. It could be modified to short-cicuit on the categoryGroups as well.
Here's a JS Fiddle demonstration.

You could use underscore:
var cat = _(categoryGroups).
chain().
pluck('Categories').
flatten().
findWhere({Id: 2}).
value();
What I'm doing here is that I'm extracting all Categories values in a single array and then grepping for the correct categories.
EDIT: sorry, didn't get your question right the first time. As the comments suggest, you might not want to use underscore just for that, but that's how I would do it :)

We are using object-scan for our data processing now. It's very powerful once you wrap your head around it. For your questions this would look like this:
// const objectScan = require('object-scan');
const lookup = (id, data) => objectScan(['Categories.Id'], {
useArraySelector: false,
abort: true,
rtn: 'parent',
filterFn: ({ value }) => value === id
})(data);
const categoryGroups = [{ Id: 1, Categories: [{ Id: 1 }, { Id: 2 }] }, { Id: 2, Categories: [{ Id: 100 }, { Id: 200 }] }];
console.log(lookup(1, categoryGroups));
// => { Id: 1 }
console.log(lookup(100, categoryGroups));
// => { Id: 100 }
console.log(lookup(999, categoryGroups));
// => undefined
.as-console-wrapper {max-height: 100% !important; top: 0}
<script src="https://bundle.run/object-scan#13.8.0"></script>
Disclaimer: I'm the author of object-scan