Question

21

Get the difference of arrays in ES6?

rated 0 times [ 23] [ 2] / answers: 1 / hits: 23766 / 8 Years ago, tue, december 6, 2016, 12:00:00

So I have two arrays:

const allLanguages = [ 'ES', 'EN', 'DE' ]

const usedLanguages = [ { id: 1, lang: 'EN' } ]

What's the quickest way to produce a new array which is the difference between these two? In old school JavaScript, you'd have to do a for loop inside another for loop, I think...

Eg:

const availableLanguages = [ 'ES', 'DE' ]

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shaynelandenb

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3 Years ago

answered 8 Years ago dawnc · Accepted Answer

You can use filter() and find() to return filtered array.

const allLanguages = [ 'ES', 'EN', 'DE' ]

const usedLanguages = [ { id: 1, lang: 'EN' } ]



var result = allLanguages.filter(e => !usedLanguages.find(a => e == a.lang));

console.log(result)

You could also map() second array and then use includes() to filter out duplicates.

const allLanguages = [ 'ES', 'EN', 'DE' ]

const usedLanguages = [ { id: 1, lang: 'EN' } ].map(e => e.lang);



var result = allLanguages.filter(e => !usedLanguages.includes(e));

console.log(result)