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Null type checks is not considered by the tests length #63
Description
There is a problem with countTypesInArray function (4-count-types.js). The tests require a solution to be 200 signs max, but in this case, we kinda lose the check for nulls.
As you know null in JavaScript has a type of object. Thus, the implementation you require will count objects but not nulls. So, the function is not suitable for checking all the JS types.
I clearly understand that such a check can be done using a ternary operator but it's not convenient and intuitive enough.
The implementation below considers this JS's quirk:
const data = [
false,
'a',
22,
'hey',
undefined,
42,
12,
true,
{ a: 12 },
{ name: 'Jack' },
'foo',
'bar',
true,
null,
undefined,
Symbol('a'),
null
];
const countTypesInArray = data => {
const h = {};
for (const item of data) {
if (typeof item === 'object' && item === null) {
h['null'] = 1;
if (h['null'] > 0) {
h['null']++;
}
} else if (typeof item in h) {
h[typeof item]++;
} else {
h[typeof item] = 1;
}
}
return h;
};
console.log(countTypesInArray(data));
So, maybe you should consider an option for making tests a little bit more loose for null checks.
Activity
[-]Null type is not considered by the tests[/-][+]Null type checks is not considered by the tests length[/+]PavelZubkov commentedon Sep 15, 2019
See my example
PavelZubkov commentedon Sep 15, 2019
Test it on input data
const data = [ null ];