merging duplicates in javascript array

Question

if i have a an array like below in JS

lineitems : [{
    quantity : 1,
    unitPrice : 10.00,
    unitPriceLessTax: 8.33,
    SKU: 'SKU123456',
    productName: 'Blue T-Shirt'
 },
 {
    quantity : 1,
    unitPrice : 10.00,
    unitPriceLessTax: 8.33,
    SKU: 'SKU123456',
    productName: 'Blue T-Shirt'
 },
 {
    quantity : 1,
    unitPrice : 48.00,
    unitPriceLessTax: 40.00,
    SKU: 'SKU78910',
    productName: 'Red Shoes'
 }]

how do i conver it to look like below

lineitems : [{
    quantity : 2,
    unitPrice : 10.00,
    unitPriceLessTax: 8.33,
    SKU: 'SKU123456',
    productName: 'Blue T-Shirt'
 },
 {
    quantity : 1,
    unitPrice : 48.00,
    unitPriceLessTax: 40.00,
    SKU: 'SKU78910',
    productName: 'Red Shoes'
 }]

basically looking to merge duplicates based on SKU

please form your code for better visibility

Saar
– Saar

2015-09-17 13:02:51 +00:00
Commented Sep 17, 2015 at 13:02 — Saar
– Saar, Commented Sep 17, 2015 at 13:02
on what you want to compare?

Muhammad Usman
– Muhammad Usman

2015-09-17 13:12:22 +00:00
Commented Sep 17, 2015 at 13:12 — Muhammad Usman
– Muhammad Usman, Commented Sep 17, 2015 at 13:12

Arash R · Accepted Answer · 2015-09-17 13:17:57Z

1

you can use associative array:

var newLineItems = new Array();
$.each(lineItems, function (index) {
    if (newLineItems[this.SKU])
        newLineItems[this.SKU].quantity += this.quantity;
    else
        newLineItems[this.SKU] = this;
});

answered Sep 17, 2015 at 13:17

Arash R

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1 Comment

Andy Over a year ago

Use an object, not an array.

Daniel Rosano · Accepted Answer · 2015-09-17 13:39:16Z

1

You can use Array.prototype.forEach()

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach

var result = []
var temp = [];
lineitems.forEach(function (element, index, array) {
    if (temp[element.SKU] === undefined)
        temp[element.SKU] = element;
    else
        temp[element.SKU].quantity += element.quantity;
});
for (var items in temp){
    result.push(temp[items]);
}

Hope it's useful

Dan

answered Sep 17, 2015 at 13:39

Daniel Rosano

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Comments

Leo Nix · Accepted Answer · 2015-09-30 13:43:07Z

0

Pure JS; Fast calculator;

<script>
    var lineItems = [{
    quantity : 1,
    unitPrice : 10.00,
    unitPriceLessTax: 8.33,
    SKU: 'SKU123456',
    productName: 'Blue T-Shirt'
 },
 {
    quantity : 1,
    unitPrice : 10.00,
    unitPriceLessTax: 8.33,
    SKU: 'SKU123456',
    productName: 'Blue T-Shirt'
 },
 {
    quantity : 1,
    unitPrice : 48.00,
    unitPriceLessTax: 40.00,
    SKU: 'SKU78910',
    productName: 'Red Shoes'
 }];

var nl =[], i=0;
var collapse = function ()
{
    if (lineItems.length<=i) return;
    if (nl[lineItems[i].SKU])
    {
        nl[lineItems[i].SKU].quantity+=lineItems[i].quantity;
    }
    else  nl[lineItems[i].SKU]=lineItems[i];
    i++;
    //lineItems.splice(0,1);
    collapse();
};
collapse();
console.log(nl);
var newLineItems = Object.keys(nl).map(function (key) {return nl[key]});
console.log(newLineItems);
console.log('new line items');
console.log(lineItems);
</script>

edited Sep 30, 2015 at 13:43

answered Sep 17, 2015 at 14:55

Leo Nix

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3 Comments

Ethan Cox Over a year ago

hi Leo, could you help me with the issue i am facing? basically when i runt the code the original Array gets overritten with value so i am assumin ghtis is because we are using "return nl[key]" how can i over come the problem where original values of "lineItems" is not touched but only "nl"

Ethan Cox Over a year ago

i have tried assigning the lineItems to another array and used the same but it still updates the original value. i have to validate the orginal array against the new one. thanks for you help

Leo Nix Over a year ago

Hi Ethan, the reason it changes the original value was due to the splice. Now I've modified the code not to splice so it should not change the original values and should also gain some performance as we're not resizing the array any longer;

user1776684 · Accepted Answer · 2015-09-17 13:21:27Z

0

Using lodash is a quick way to manage your collections:

result = _.uniq(lineitems, "SKU");

answered Sep 17, 2015 at 13:21

user1776684

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