Does your function return the value you expect from the following function calls?

contains(["a", "b", "c"], "1")
contains("abc", "1")
contains(null, "1")
contains(undefined, "1")

Now, it handles correctly.

This test cannot not yet confirm that the function correctly returns false when the first argument is an array.
This is because contains(["a", "b", "c"]) is the executed as contains("[a", "b", "c"], undefined), which could also return false simply because "undefined" is not a key of the array.

Arrays are objects, with their indices acting as keys. A proper test should use a valid
key to ensure the function returns false specifically because the input is an array, not because the key is missing.

Currently your function will return true in these two function calls.

• contains(["a", "b", "c"], "1")
• contains("abc", "1")

Now, I understand what you are telling, sir. I changed the function first:
`function contains(obj, x) {
if (
typeof obj !== "object" ||
obj === null ||
Array.isArray(obj)
) {
return false;
}

return Object.prototype.hasOwnProperty.call(obj, x);

}

module.exports = contains;`

And the test:
test("contains() handles arrays, strings, null, and undefined safely", () => { expect(contains([["a", "b", "c"], "1"])).toBe(false); expect(contains(["abc", "1"])).toBe(false); })

Please check if it is okay; otherwise, I will change.

Does your function return what you expect in the following function calls?

countWords("Hello,World! Hello World!");
countWords("constructor constructor");
countWords("          Hello World      ");

Note: The spec is not clear about exactly what to expect from these function calls. This is just for self-check.

Thank you for pointing out the bugs. Now, this should work for all cases.

`function countWords(str) {
const words = str
.toLowerCase()
.replace(/[^a-zA-Z0-9\s]/g, '') // replace punctuation with space
.trim()
.split(/\s+/); // split on any white space

const countObj = Object.create(null);

for (const word of words) {
countObj[word] = (countObj[word] || 0) + 1;
}

// Object.entries() converts object to array
const sortedArray = Object.entries(countObj).sort((a, b) => b[1] - a[1]);

// Object.fromEntries() coverts the sorted array to object
return Object.fromEntries(sortedArray);
}`

I think the question is asking for the "expected output", not the actual output.

// a) What is the target output when totalTill is called with the till object
// £4.40