How to Remove Duplicates From an Array in JavaScript
Ferenc Almasi • 2020 July 30 •
1 min read
Have you ever had trouble writing out the same filtering function for arrays again and again to remove duplicates? Did you know that you can do the same by simply combining the spread operator with a new Set? Doesn't get any shorter than this:
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// Use the spread operator with a new Set to create
// an array containing only unique values
const food = [‘🌽’, ‘🌽’, ‘🥔’, ‘🍆’, ‘🍆’];
const uniqueFood = [...new Set(food)];
console.log(uniqueFood);
// Results in the following output:
[‘🌽’, ‘🥔’, ‘🍆’];Apart from using Sets, you can also use a filter, to filter out duplicate values:
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const food = [‘🌽’, ‘🌽’, ‘🥔’, ‘🍆’, ‘🍆’];
const uniqueFood = food.filter((f, i) => food.indexOf(f) == i);
// Gives the same result, just like using Set
console.log(uniqueFood);
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