Creating string length function in JavaScript

Question

Your task is to write a function called stringLength that accepts a string as a parameter and computes the length of that string; however, as you may have guessed, you are not allowed to use the length property of the string!

Instead, you'll need to make use of the string method called slice.

My program is not creating the right output. Please explain the error in my code.

function stringLength(string) {
let start =0;
let end= string.slice(0, "");
let result=0;
for(let i=start; i<=end; i++){
result++;
}
 return result;
}

My output is 1

Whereas the output should return the length of the given string.

What is slice(0, "") supposed to do? Btw [...string].length — Jonas Wilms
– Jonas Wilms, Commented Apr 28, 2019 at 19:45
@JonasWilms i thought it would give the end of the given string, but clearly i was wrong. — Shreeya Bhetwal
– Shreeya Bhetwal, Commented Apr 28, 2019 at 21:11

Fundhund · Accepted Answer · 2019-04-28 20:22:53Z

2

You could try this:

function stringLength(string) {

  let index = 0;

  while (string.slice(index) !== '') {
    index++;
  }

  return index;
}

string.slice(index) will return the substring from character at index index until the end of the string. If index exceeds the biggest index in the string, it returns an empty string. That's how you know you have to stop counting.

You could even do it without slice at all:

function stringLength(string) {

    let count = 0;

    for(let char of string) {
        count++;
    }

    return count;
}

answered Apr 28, 2019 at 20:22

Fundhund

1415 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

zeev gerstner · Accepted Answer · 2019-04-28 19:47:45Z

0

Slice can get one parameter for start index and it will slice till the end or two parameters for start index and end index. You can't put "" as a parameter Look here

answered Apr 28, 2019 at 19:47

zeev gerstner

154 bronze badges

Comments

Guilherme Lemmi · Accepted Answer · 2019-04-28 20:40:45Z

0

You can use the method split with '' as parameter, which will return an array with all the letters of the string. Then, just iterate through this array using the method reduce, adding 1 to a counter for each letter, like below:

function stringLength(string) {
        return string.split('').reduce(function (length) {
            return length + 1;
        }, 0);
}

With ES6 syntax, it gets even shorter:

function stringLength(string) {
        return string.split('').reduce((length) => length + 1, 0);
}

answered Apr 28, 2019 at 20:40

Guilherme Lemmi

3,4977 gold badges33 silver badges32 bronze badges

Collectives™ on Stack Overflow

Creating string length function in JavaScript

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related