How do I remove certain elements matching criteria from an array in javascript?

Question

I have an array.

const arr = ['apple', 'banana', 'pear', 'orange', 'peach'];

The test function is like this.

function test(str) {
  return str.length >= 6;
}

I can find the elements easily with filter method. But I want to remove these elements from the array.

The result should be

['apple', 'pear', 'peach']

Answer 1

Javascript has a function just for this, Array.prototype.filter :

const arr = ['apple', 'banana', 'pear', 'orange', 'peach'];
function test(str) {
    return str.length >= 6;
}

// we need to negate the result since we want to keep elements where test returns false
console.log(arr.filter(x => !test(x)));
// logs: ['apple', 'pear', 'peach']

Answer 2

Beside the given Array#filter approach

array.filter(string => !test(string))

you could take the advantage of a functional approach which takes a function and retuns the negated result of it.

 function test(str) { return str.length >= 6; } function not(fn) { return (...args) => !fn(...args); } const array = ['apple', 'banana', 'pear', 'orange', 'peach'], result = array.filter(not(test)); console.log(result);