London | 26-ITP-Jan | Miriam Jorna | Sprint 1 | Data Groups#1126
London | 26-ITP-Jan | Miriam Jorna | Sprint 1 | Data Groups#1126miriamjorna wants to merge 1 commit intoCodeYourFuture:mainfrom
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You missed updating Sprint-1/refactor/includes.js.
| const median = list.splice(middleIndex, 1)[0]; | ||
| return median; | ||
| // filter only numbers from the list | ||
| const numbers = list.filter(item => typeof item === "number"); |
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Do you plan to consider also -Infinity, Infinity, and NaN in the median calculation (and in the functions in implement/max.js and implement/sum.js)?
| test("given an array with no duplicates, it returns a copy of the original array", () => { | ||
| expect(dedupe([1, 2, 3])).toEqual([1, 2, 3]); | ||
| }); |
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Your function implementation is correct. However, this test could be improved to better ensure
that any future changes continue to align with the expected behavior:
Then it should return a copy of the original array
This test should fail if the function returns the original array (instead of a copy of the original array).
The current test checks only if both the original array and the returned array contain identical elements.
In order to validate the returned array is a different array, we need an additional check.
Can you find out what this additional check is?
| test("given an array with non-number values, returns the max and ignores non-numeric values", () => { | ||
| expect(findMax(['hey', 10, 'hi', 60, 10])).toEqual(60); | ||
| }); |
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When a string representing a valid numeric literal (for example, "300") is compared to a number,
JavaScript first converts the string into its numeric equivalent before performing the comparison.
As a result, the expression 20 < "300" evaluates to true.
To test if the function can correctly ignore non-numeric values,
consider including a string such as "300" in the relevant test cases.
| test("given an array with decimal numbers, returns the correct total sum", () => { | ||
| expect(sum([1.5, 2.5, 3.0])).toEqual(7); | ||
| }); |
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Decimal numbers in most programming languages (including JS) are internally represented in "floating point number" format. Floating point arithmetic is not exact. For example, the result of 46.5678 - 46 === 0.5678 is false because 46.5678 - 46 only yield a value that is very close to 0.5678. Even changing the order in which the program add/subtract numbers can yield different values.
So the following could happen
expect( 1.2 + 0.6 + 0.005 ).toEqual( 1.805 ); // This fail
expect( 1.2 + 0.6 + 0.005 ).toEqual( 1.8049999999999997 ); // This pass
expect( 0.005 + 0.6 + 1.2 ).toEqual( 1.8049999999999997 ); // This fail
console.log(1.2 + 0.6 + 0.005 == 1.805); // false
console.log(1.2 + 0.6 + 0.005 == 0.005 + 0.6 + 1.2); // falseCan you find a more appropriate way to test a value (that involves decimal number calculations) for equality?
Suggestion: Look up
- Checking equality in floating point arithmetic in JavaScript
- Checking equality in floating point arithmetic with Jest
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Have done the exercises for the Sprint-1 homework.
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