Activation Keys

function solve(input) {

    let activationKey = input.splice(0,1).toString();
    let commands = input.shift();
    while(commands !== 'Generate'){

     let separatedCommands = commands.split('>>>');
     if(separatedCommands[0] === 'Contains'){
        let neededSubstringg = separatedCommands[1];
        if(activationKey.includes(neededSubstringg)){
            console.log(`${activationKey} contains ${neededSubstringg}`);
        }else{
            console.log(`Substring not found!`);
        }
    } else if(separatedCommands[0] === 'Flip'){
        let startIndex = Number(separatedCommands[2]);
        let endIndex = Number(separatedCommands[3]);
        let neededChar =  activationKey.substring(startIndex,endIndex);
         if(separatedCommands [1] === 'Upper'){
            let replaced = activationKey.substring(startIndex,endIndex).toUpperCase();
            activationKey = activationKey.replace(neededChar, replaced);
            console.log(activationKey);
         }else if(separatedCommands[1] === 'Lower'){
            let replaced = activationKey.substring(startIndex,endIndex).toLowerCase();
            activationKey = activationKey.replace(neededChar, replaced);
            console.log(activationKey);
         }
     }else if(separatedCommands[0] === 'Slice'){
         let startIndex = Number(separatedCommands[1]);
         let endIndex = Number(separatedCommands[2]);
         if((startIndex >= 0 && endIndex >= 0) && (startIndex < activationKey.length && activationKey.length > endIndex)){
     let slicedActivationKey = activationKey.substring(startIndex,endIndex);
     activationKey = activationKey.replace(slicedActivationKey,'');
         }
         console.log(activationKey);
    }
    commands = input.shift()
    }

    console.log(`Your activation key is: ${activationKey}`);

    }