javascript count letters in string code example

Example 1: count occurrences of character in string javascript

var temp = "This is a string.";
var count = (temp.match(/is/g) || []).length;
console.log(count);

Output: 2

Explaination : The g in the regular expression (short for global) says to search the whole string rather than just find the first occurrence. This matches 'is' twice.

Example 2: how get count of letters in javascript

//when use length for string this will be return the count of charactor 
//in string
$("#about_me_textarea").val().length

Example 3: how to count specific letters in string js

console.log(("str1,str2,str3,str4".match(/,/g) || []).length); //logs 3

console.log(("str1,str2,str3,str4".match(new RegExp("str", "g")) || []).length); //logs 4

Example 4: count value a to b character javascript

const recorrences = ['a', 'b', 'c', 'a', 'b','a']
                .map(i => !!~i.indexOf('a'))
                .filter(i => i)
                .length;
console.log(`recorrences ${recorrences}`) 
//recorrences 3

Example 5: count value a to b character javascript

let counter = str => {
  return str.split('').reduce((total, letter) => {
    total[letter] ? total[letter]++ : total[letter] = 1;
    return total;
  }, {});
};

counter("aabsssd"); // => { a: 2, b: 1, s: 3, d: 1 }

Example 6: count characters in typescript

function count (string) {  
  var count = {};
  string.split('').forEach(function(s) {
     count[s] ? count[s]++ : count[s] = 1;
  });
  return count;
}