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main.js
run
preview
console
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);
});
});
Console
"result 3: "
,
true
,
"result 3: "
,
false
,
"result 3: "
,
false
,
"result 1: "
,
false
,
"result 2: "
,
false
,
"result 3: "
,
true
,
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