I was wondering why the below code returns a memory allocation error?

var countValidWords = function(sentence) {
    let words = [];
    for(let i = 0; i < sentence.length;   i){
        let word = '';
        while(sentence[i] !== ' '){
            word  = sentence[i];
              i;
        }
        if(word !== '')
            words.push(word);
    }
    console.log(words);
};

I'm simply trying to build an array of words from the inputted sentence (words can be separated by more than one space).

CodePudding user response：

If the sentence doesn't end with a space, the while loop never ends, because it doesn't check if it has gone past the end of the string. As a result, you go into an infinite loop appending undefined to word, until you run out of memory.

Add a check that i is within the string length there.

var countValidWords = function(sentence) {
    let words = [];
    for(let i = 0; i < sentence.length;   i){
        let word = '';
        while(i < sentence.length && sentence[i] !== ' '){
            word  = sentence[i];
              i;
        }
        if(word !== '')
            words.push(word);
    }
    console.log(words);
};

<iframe name="sif1" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

CodePudding user response：

The while clause needs to check for i getting out of bounds:

while(i < sentence.length && sentence[i] !== ' ')

CodePudding user response：

How about this? It's not the most optimized version you might find but it works. You had an infinite loop on the while.

var countValidWords = function(sentence) {
    let words = [];
    let word = ''
    for(let i = 0; i < sentence.length;   i){
        if(sentence[i] != '' && sentence[i] != ' '){
          word  = sentence[i];
        }
        if(sentence[i] == ' ' || sentence[i   1] === undefined){
          words.push(word);
          word = '';
        }
    }
    console.log(words);
};