String Characters - Group & Count

Array without IndexOf.js

var myString = "aaAbbcdeffff".toUpperCase()

// potential bucket for one of every letter
var letters = [] // ex. ["a", "b", "c", "d"]
var counts = []  // ex. [3, 2, 1, 1]

// loop through every letter in string
for (i=0; i < myString.length; i++) {
	var char = myString[i]

	// see if character already exists in 'letters' array, and if so, we need to return the index
	var charPos = -1
	for (j=0; j < letters.length; j++) {
		var letterChar = letters[j] //ex. "a"
        var valueAlreadyExists = char === letterChar
        if (valueAlreadyExists) {
			charPos = j
        }
    }

	//var charPos = letters.indexOf(char) // ex. 1


	// see if character exists in letters
	var valueAlreadyExists = charPos >= 0

	if (!valueAlreadyExists) {
		// doesn't exist - insert property and set value to one
		letters.push(char)
		counts.push(1)

    } else {
		// already exists - increment value
		// find position of char in letters array
		counts[charPos] = counts[charPos] + 1

    }
	
}

console.log(letters,counts)

Arrays.js

var myString = "aaAbbcdeffff".toUpperCase()

// potential bucket for one of every letter
var letters = [] // ex. ["a", b", "c", "d"]
var counts = []  // ex. [3, 2, 1, 1]

// loop through every letter in string
for (i=0; i < myString.length; i++) {
	var char = myString[i]
	var charPos = letters.indexOf(char) // ex. 1

	// see if character exists in letters
	var valueAlreadyExists = charPos >= 0

	if (!valueAlreadyExists) {
		// doesn't exist - insert property and set value to one
		letters.push(char)
		counts.push(1)

    } else {
		// already exists - increment value
		// find position of char in letters array
		counts[charPos] = counts[charPos] + 1

    }
	
}

console.log(letters,counts)

Dictionary.js

var myString = "aabc"
var chars = {}

for (i=0; i < myString.length; i++) {
	var char = myString[i]
	// see if i have an old value
	var valueAlreadyExists = true //false
	if (valueAlreadyExists) {
		// already exists - increment value
		chars[char] = chars[char] + 1
    } else {
		// doesn't exist - insert property and set value to one
		chars[char] = 1
    }
	
}

console.log(chars)

Reduce.js

[...myString].reduce((acc, char) => {
	acc[char] = (acc[char] || 0) + 1
    return acc
}, {})