Westmidlands/Millena-Mesfin/Module Data Groups Sprint#2/Week 10 #485
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| for (const key in author) { | ||
| console.log(key); | ||
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Can you modify this to output the property values instead of property names?
| function contains(obj,key) { | ||
| return (key in obj); | ||
| } |
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Consider the following two approaches for determining if an object contains a property:
let obj = {}, propertyName = "toString";
console.log( propertyName in obj ); // true
console.log( Object.hasOwn(obj, propertyName) ); // false
Which of these approaches suits your needs better?
For more info, you can look up JS "in" operator vs Object.hasOwn.
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Thank you cj, I got to differentiate the (propertyName in obj) suits to my function.
| test("contains an invalid parameter like array should return false" ,() => { | ||
| const obj = ["code","your","future"]; | ||
| expect(contains(obj,'age')).toBe(false); | ||
| expect(contains(obj,'address')).toBe(false); | ||
| }); |
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An array is a kind of object in JS.
The indexes serve as the keys (or property names) in an array. So contains(["code","your","future"], '0') would return true.
If the function needs to return false when the parameter is an array, the function will need to check if the parameter is an array or not.
| test("An array with invalid input should throw an error", () => { | ||
| const count = ["hello", "hey", "hey", "hello", "hello", "hi"]; | ||
| const expectedOutput = {hello: 3, hey: 2, hi: 1 }; | ||
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| expect(tally(count)).toEqual(expectedOutput); | ||
| }); |
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The description and the code does not match.
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