CODEWITHSUNDEEP
javascriptnode.js
Martin Thompson
Martin Thompson

Reputation: 3755

Find difference in array only using key using lodash

How can I find all values in an array A - where the key is not in array B ( a bit like a SQL Not In ) . I don't want to compare the whole array , just one property - but I do want to return all fields for the differences using lodash ( or simpler ) 

const arrayA = [
  { sku:"1", name:"one"},
  { sku:"2", name:"two"}
]
const arrayB = [
  { sku:"1", name:"One Product"},
  { sku:"2", name:"Two Product"},
  { sku:"3", name:"Three Product"}
]

The results should be :

{ sku:"3", name:"Three Product"}

Thank you for your time.

Upvotes: 1

Views: 45

Answers (2)

Henry Tseng
Henry Tseng

Reputation: 3333

You could also use:

const arrayA = [
  { sku:"1", name:"one"},
  { sku:"2", name:"two"}
];
const arrayB = [
  { sku:"1", name:"One Product"},
  { sku:"2", name:"Two Product"},
  { sku:"3", name:"Three Product"}
];

let diff = _.differenceWith(arrayB, arrayA, (a, b) => _.isEqual(a.sku, b.sku) );

Upvotes: 1

nem035
nem035

Reputation: 35501

You don't really need lodash for this. What you need is to filter the second array and eliminate all elements existing in the first array.

const arrayA = [
  { sku:"1", name:"one"},
  { sku:"2", name:"two"}
]
const arrayB = [
  { sku:"1", name:"One Product"},
  { sku:"2", name:"Two Product"},
  { sku:"3", name:"Three Product"}
]

console.log(
  // filter B such that we only leave items from B that are not in A
  arrayB.filter(b => 
    !arrayA.some(a => a.sku === b.sku)
  )
)

Upvotes: 0

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