Using replace string method inside forEach

Question

I have an array full of strings which I'd like to loop over and replace any occurrences of '123' with ''.

The desired result would be: ['hello', 'cats', 'world', 'dogs']

let arr = ['he123llo', 'cats', 'wor123ld', 'dogs'];

arr.forEach(x => {
  x.replace('123', '');
});

const replacedStrings = arr.map(word => word.replace(/123/g, '')) — Yevhen Horbunkov
– Yevhen Horbunkov, Commented Dec 5, 2020 at 21:51
forEach() returns undefined, you're supposed to use Array.prototype.map() insted and, by the way, it's better to use .replace(/123/g, '') if you want to replace all occurrences of unneeded substring — Yevhen Horbunkov
– Yevhen Horbunkov, Commented Dec 5, 2020 at 21:53

CertainPerformance · Accepted Answer · 2020-12-05 21:51:19Z

7

Use .map instead, if you can - return the .replace call in the callback:

let arr = ['he123llo', 'cats', 'wor123ld', 'dogs'];

const result = arr.map(x => x.replace('123', ''));
console.log(result);

If you have to mutate the array in-place, then take the index as well, and assign the .replace call back to that index in the array:

let arr = ['he123llo', 'cats', 'wor123ld', 'dogs'];

arr.forEach((x, i) => arr[i] = x.replace('123', ''));
console.log(arr);

answered Dec 5, 2020 at 21:51

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