使用map返回一个空数组，而不是[0]零

Question

I have some working code that will take a string of words and return an array of the length of each word. For example:

let str = "hello world" returns [5, 5]

My issue is if str = "" (empty) it will return [0] instead of [] (empty array) which is what I'd like it to do. Does anyone have any ideas how I can alter my code to return this? Thank you!

const arr = str.split(' ');
return arr.map(words => words.length);

Answer 1

You can return an empty array if the string is equal to '' (empty string):

 function count(str) { return (str === '') ? [] : str.split(' ').map(({length}) => length); } console.log(count('hello world')); console.log(count('')); 

Answer 2

Add a filter at the end.

 const str = ""; const arr = str.split(' '); console.log(arr.map(words => words.length).filter(count => count != 0));