JavaScript: Filter out the non-unique values in an array
JavaScript fundamental (ES6 Syntax): Exercise-22 with Solution
Write a JavaScript program to filter out the non-unique values in an array.
- Use new Set() and the spread operator (...) to create an array of the unique values in arr.
- Use Array.prototype.filter() to create an array containing only the unique values.
Sample Solution:
JavaScript Code:
//#Source https://bit.ly/2neWfJ2
const filter_Non_Unique = arr => arr.filter(i => arr.indexOf(i) === arr.lastIndexOf(i));
console.log(filter_Non_Unique([1, 2, 2, 3, 4, 4, 5]));
console.log(filter_Non_Unique([1, 2, 3, 4]));
Sample Output:
[1,3,5] [1,2,3,4]
Pictorial Presentation:
Flowchart:

Live Demo:
See the Pen javascript-basic-exercise-1-22 by w3resource (@w3resource) on CodePen.
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Previous: Write a JavaScript program to get every nth element in an given array.
Next: Write a JavaScript program to filter out the non-unique values in an array, based on a provided comparator function.
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JavaScript: Tips of the Day
Returns an array of n-tuples of consecutive elements
Example:
const tips_arr = (n, arr) => n > arr.length ? [] : arr.slice(n - 1).map((v, i) =>[...arr.slice(i, i + n - 1), v]); console.log(tips_arr(2, [1, 2, 3, 4, 5])); console.log(tips_arr(3, [1, 2, 3, 4, 5])); console.log(tips_arr(5, [1, 2, 3, 4]));
Output:
[[1, 2], [2, 3], [3, 4], [4, 5]] [[1, 2, 3], [2, 3, 4], [3, 4, 5]] []
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