Question

Write a JS program that keeps a string inside it’s context and can execute different commands that modify or output the string on the console.

append(str) – add str to the end of the internal string
removeStart(n) – remove the first n characters from the string, n is an integer
removeEnd(n) – remove the last n characters from the string, n is an integer
print – output the stored string to the console

Input:
You will receive an array of strings. Each element is a command that may be a single word or contain an argument, separated by space.

Output:
Whenever you receive the command print, output should be the printed on the console. Any other operations are carried onto the internal storage of the function.

Examples:

Sample Input:

['append hello',

 'append again',

 'removeStart 3',

 'removeEnd 4',

 'print']

 

Output:
loa

---

Sample Input:

['append 123',

 'append 45',

 'removeStart 2',

 'removeEnd 1',

 'print']

Output:
34

Answer 1

Here is my JavaScript code (solution):
 

function solve(commands){

    let processor = (function(){
        let text = '';

        return function processor(commandString){
            let commandTokens = commandString.split(' ');

            switch (commandTokens[0]){
                case 'append':
                    text+=commandTokens[1];
                    break;
                case 'removeStart':
                    text = text.slice(Number(commandTokens[1]));
                    break;
                case 'removeEnd':
                    text = text.slice(0,text.length-Number(commandTokens[1]));
                    break;
                case 'print':
                    console.log(text);
                    break;
            }
        }
    })();

    for(let commandString of commands){
        processor(commandString);
    }
}

console.log(solve(['append 123',
        'append 45',
        'removeStart 2',
        'removeEnd 1',
        'print']
));