Look for characters and if exists increment 1

I am trying to create a folder using javascript but before I do that I need to check if the folder exists and if it does increase the number by 1.

Here's my input name: The ABC Group

I want javascript to remove ‘The’ and move it to the end and then finally add a code based on the first 4 characters followed by a number. If the first 4 characters don’t exist in the directory then it will start 01 and increment from there on.

Here's what I want to output:

I.e. ABC Group, The (ABCG01)

I am new to javascript but I have so far worked out how to do everything apart from the number part which I am stuck on.

Here's my code:

var clientName = "the ABC company"; 

// Change Case - START
const toCapitaliseCase = (phrase) => {
return phrase
.split(' ')
.map(word => word.charAt(0).toUpperCase() + word.slice(1))
.join(' ');
};

let capitalise = toCapitaliseCase(clientName);
// Change Case - END
// Format Client Name if starts with 'The' - START)

if (capitalise.startsWith('The ')) {  
let words = capitalise.split(' ');
let the = words[0];
let theSlice = capitalise.slice(4);
let comma = ', ';
let name = theSlice.concat('', comma, the);
let name2 = name.replace(/[^0-9a-zA-Z]/g, "");
let theSlice2 = name2.slice(0,4);
var upper = theSlice2.toUpperCase(); // output - "i am a crazy string, make me normal!"
let numbecccr = '101';
let theSlice3 = numbecccr.slice(1);



let FullCompiledName = theSlice.concat('', comma, the, ' (',upper, theSlice3, ')');

console.log(FullCompiledName);
// Format Client Name - START

}

I put your code into a function, in which I counted the number up each time the function gets called.

var clientName = "the ABC company"; 

function createName(clientName) {
    this.number = this.number || 0;
    // Change Case - START
    const toCapitaliseCase = (phrase) => {
        return phrase
        .split(' ')
        .map(word => word.charAt(0).toUpperCase() + word.slice(1))
        .join(' ');
    };

    let capitalise = toCapitaliseCase(clientName);
    // Change Case - END
    // Format Client Name if starts with 'The' - START)

    if (capitalise.startsWith('The ')) {  
        let words = capitalise.split(' ');
        let the = words[0];
        let theSlice = capitalise.slice(4);
        let comma = ', ';
        let name = theSlice.concat('', comma, the);
        let name2 = name.replace(/[^0-9a-zA-Z]/g, "");
        let theSlice2 = name2.slice(0,4);
        var upper = theSlice2.toUpperCase(); // output - "i am a crazy string, make me normal!"
        this.number++;
        let num = this.number;
        if(('' + num).length == 1) {
            num = '0' + num;
        }



        let FullCompiledName = theSlice.concat('', comma, the, ' (',upper, num, ')');

        return FullCompiledName;
    }
}

console.log(createName(clientName));
console.log(createName(clientName));