function alphabetSubsequence(str) {
    // catch null or undeined
    if (str === null || str === undefined) {
        alert("Nothing comes from nothing")
        return false
    }
    
    // catch non-strings
    if (typeof(str) !== "string") {
        alert("Only put strings in this thing!")
        return false
    }
    
    // return false if duplicates exist
    const splitted = str.split("")
    const noDupes = []
    for (let i=0; i<splitted.length; i++) {
        noDupes.includes(splitted[i]) ?
        noDupes.push("DUPE") :
        noDupes.push(splitted[i])
    }
    if (noDupes.includes("DUPE")) return false
    
    // check for ascending order in alphabet
    const sorted = [...noDupes].sort()
    for (let c=0; c<sorted.length; c++) {
        if (sorted[c] !== noDupes[c]) return false
        return true
    }
    
}



/**
* 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 when no 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);
    });
    
    it('returns true when no duplicates and is ascending a - z order check #2 ', () => {
        // arrange
        const str = 'lquz';
        
        // act
        const result = alphabetSubsequence(str);

        // log
        console.log("result 3: ", result);
        
        // assert
        expect(result).toBe(true);
    });
    
    it('alerts and returns false if input is not type string', () => {
        // arrange
        const input = 42;
        
        // act
        const result = alphabetSubsequence(input);

        // log
        console.log("result 3: ", result);
        
        // assert
        expect(result).toBe(false);
    });
    
    it('alerts and returns false if input is undefined', () => {
        // arrange
        const input = undefined;
        
        // act
        const result = alphabetSubsequence(input);

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