function alphabetSubsequence(str) {
    //set an alphabet array to check order against...
    const alphabet = ['a', 'b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'];
    //return vaue is false by default;
    let returnValue = false;
    
    for (i = 1; i < str.length; i++){
        let char = str.charAt(i);
        let lastChar = str.charAt(i-1);
        if( alphabet.indexOf(char) > alphabet.indexOf(lastChar)){
            //mark the return value as true, if the whole loop is successful the true will be returned
            returnValue = true;
        }else {
            returnValue = false;
            //end for loop and exit once the first false is found;
            break;
        }}
    return returnValue;
}



/**
* Test Suite 
*/
describe('alphabetSubsequence()', () => {
    it('returns false when it has duplicate letters', () => {
        // arrange
        const str = 'effg';
        
        // act
        const result = alphabetSubsequence(str);

        // log
        console.log("result 1: ", result);
        
        // assert
        expect(result).toBe(false);
    });

    it('returns false when NOT in ascending a - z order', () => {
        // arrange
        const str = 'cdce';
        
        // act
        const result = alphabetSubsequence(str);

        // log
        console.log("result 2: ", result);
        
        // assert
        expect(result).toBe(false);
    });
    
    it('returns true whenno duplicates and is ascending a - z order ', () => {
        // arrange
        const str = 'ace';
        
        // act
        const result = alphabetSubsequence(str);

        // log
        console.log("result 3: ", result);
        
        // assert
        expect(result).toBe(true);
    });
});