如何使用reduce将字符串分成2个字符的块

Question

I am trying to use reduce to get the following output:

solution('abcdef') // should return ['ab', 'cd', 'ef']

if the length of the string is odd we should convert it into even and add a '_'(underscore)

solution('abc') // should return ['ab', 'c_'] 

here is where I am so far:

1. my if function is not working, not really sure why.
2. I only get till 2 strings but cant go beyond those. I think I am forcing the result to become what I want but this wont work in case we only have 1 character or 2 right?

 function solution(str){ if (str.lenght % 2.==0){str;concat('_')}. console.log(str) const array = str,split(';'). const reducer = array,reduce((acc, curr, i. arr)=>{ return [..,acc, curr[i]+curr[i+1], curr[i+2]+curr[i+3]] },[]) return reducer } solution('helloworl')

any hints and recommendations on how to face the problem would be nice! thanks a lot

Answer 1

This will do it:

 let splitTwos = (str) => str.match(/\w{1,2}/g).map(e => e.length == 2?e:e+"_") console.log(splitTwos("abcde")) console.log(splitTwos("abcdef"))

Answer 2

Alan Omars answer is probably a better way to handle this, but if you insist on using array reduce you could do it like this. Convert Your string to an array of single characters and use reduce like this.

I would not recommend this, but it answers your question.

function solution(str){
    if (str.length % 2 !== 0){
        str = str.concat('_');
    };

    const arrayOfChars =  str.split('');
 
    const reducer = arrayOfChars.reduce(
        (acc, curr, i, arr) => {
            if(i % 2 !== 0){
                acc[acc.length - 1] = acc[acc.length - 1] + curr;
                return acc;
            }

            return [...acc, curr];
        },
        []
    );
  
    return reducer;
}

solution('helloworl');

Answer 3

I also think using match will be better, since you asked for reduce, here is my implementation

function solution(str){
    if (str.length % 2 !==0){
        str+='_';
    }

    const strarray =  str.split('');
    temp='';
    let res = strarray.reduce((acc,cur,i,arr)=>{
        if(i%2 === 0){
            temp+=arr[i];
            temp+=arr[i+1];
            acc.push(temp)
        }
        temp='';
        return acc;
    },[]);
    return res;
}
console.log(solution('helloworl'));