Search a string to find all the letters in JavaScript [closed]

Question

I search for the word "i" in the text, but it only shows the first "i" and does not show the rest of "i" I want you to show me the whole text though Help me please

const searchItem = () => {
  const source = "Lorem ipsum dolor sit amet consectetur adipisicing elit."
  const searchDate = "i";
  for (let i = 0; i < source.length; i++) {
    let res = source.search(searchDate);
    if (res > 0) {
      document.getElementById("demo").innerHTML = res;
    } else if (res < 0) {
      document.getElementById("demo").innerHTML = "No results found";
    }
  }
}

<button onclick="searchItem()">Try it</button>

<p id="demo"></p>

Answer 1

You can use String#indexOf with the fromIndex argument to continuously search for the string.

const searchItem = () => {
  const source = "Lorem ipsum dolor sit amet consectetur adipisicing elit."
  const searchDate = "i";
  const indexes = [];
  let i, prev = 0;
  while((i = source.indexOf(searchDate, prev)) !== -1){
    indexes.push(i);
    prev = i + searchDate.length;
  }
  if (indexes.length > 0) {
    document.getElementById("demo").innerHTML = indexes;
  } else {
    document.getElementById("demo").innerHTML = "No results found";
  }
}

<button onclick="searchItem()">Try it</button>

<p id="demo"></p>

Answer 2

.search() returns the index of the first match. It does not search the whole string.

---

Since the for loop in the code isn't used, You're probably trying use that loop to compare each char in the string;

const searchItem = () => {
    const source = "Lorem ipsum dolor sit amet consectetur adipisicing elit."
    const searchDate = "i";
    let res = 0;

    // For each character in source
    for (let i = 0; i < source.length; i++) {
        
        // If current char matches searchDate
        if (source[i] === searchDate) {
        
            // Bumb result counter
            res++;
        }
    }

    // After looping through all the chars, show result based on res
    if (res > 0) {
        document.getElementById("demo").innerHTML = res;
    } else if (res < 0) {
        document.getElementById("demo").innerHTML = "No results found";
    }
}

<button onclick="searchItem()">Try it</button>

<p id="demo"></p>

Answer 3

const searchItem = () => {
  const str = "Lorem ipsum dolor sit amet consectetur adipisicing elit."
  const res = str.split("i").length - 1;
  if (res > 0) {
    document.getElementById("demo").textContent = res;
  } else {
    document.getElementById("demo").textContent = "Invalid";
  }
}

<button onclick="searchItem()">Try it</button>

<p id="demo"></p>

If your aim is to only find the occurrences of letters in word then that can be done by simple split method.

const str = "Lorem ipsum dolor sit amet consectetur adipisicing elit.";
const result = str.split("i").length - 1;
console.log(result);

Answer 4

Seems to me like you're trying to count the occurrences within a string, this should do:

var findOccurrences = () => {
   var searchQuery = document.getElementById('searchQuery').value;
   var source = document.getElementById('source').value;

   var regExp = new RegExp(searchQuery, 'g');
    
   var match = source.match(regExp);
   var occurrences = 0;
   
   if(match) {
    occurrences = match.length;
   }

   document.getElementById('demo').innerHTML = occurrences > 0 ? occurrences : "No results found";
 }

<input id="source" value="Lorem ipsum dolor sit amet consectetur adipisicing elit."/>
<input id="searchQuery" />
<button onclick="findOccurrences()">Try it</button>
<div id="demo"></div>