Function with a for loop and if else statement- letters after-CodePudding

// YOUR CODE
let letters = '';

function lettersAfter(haystack, needle, limit){
    ('any value','a', 2);
    for(let i = 0; i < haystack.length; i  ){
        console.log(i);
        if(haystack[i] === needle){
            for(let j = 0; j < limit; j  ) {
                console.log(j);
             let innerChar = haystack[i   j   1];
            console.log(innerChar);
         letters  = innerChar;
         console.log(letters);

         }  
return letters;
        }
    }
}

// DO NOT EDIT BELOW

module.exports = lettersAfter;

I am doing tests (that are not written by me) and I should get the values listed below:

lettersAfter('any value','a', 2); // ==> ny lettersAfter('indefatigable', 'a', 4); // => tiga

I receive ==>nytiga

I can't figure out why it is pushing the two of them together, functions as much information that can be given is super helpful, I am a beginner!

CodePudding user response：

You have to move the letters variable initialisation into the function scope. That way every time you run the function the previous value gets erased.
Since the variable is globally-scoped so far, every value gets appended to the old value.

Also, please try to format your code a bit better next time. I advise using Prettier or some other code formatter.

I created a jsfiddle with the adjusted code, it can be found on this link.

function lettersAfter(haystack, needle, limit) {
  let letters = '';
  for (let i = 0; i < haystack.length; i  ) {
    if (haystack[i] === needle) {
      for (let j = 0; j < limit; j  ) {
        let innerChar = haystack[i   j   1];
        letters  = innerChar;
      }
      return letters;
    }
  }
}

console.log(lettersAfter('any value', 'a', 2));
console.log(lettersAfter('indefatigable', 'a', 4))

CodePudding user response：

Since letters is a global variable in context to the file where function exists it forms a closure with the function hence the value keeps appending . You can read more about closures here https://developer.mozilla.org/en-US/docs/Web/JavaScript/Closures

To avoid the closure you should always put the variable inside the lexical scope of the function.