Hey there, I'm facing a challenge in my JavaScript course. The exercise requires the creation of a function that filters an array to only keep strings with less than 10 characters.
I've made several attempts at solving this problem, but haven't succeeded yet.
function filterStrings(array) {
return array.filter(function(el) { el.length < 10 } );
}
If anyone could provide some guidance or help, it would be greatly appreciated!
Everything is running smoothly.
function validUserNames(array) {
return array.filter(function(el) { return el.length < 10 } );
}
console.log(validUserNames(['foo', 'bar', 'baz', 'foobarbazzz']));
Simply inserting a return statement inside the filter function resolves the issue of it returning undefined. The filter function necessitates a predicate function, which must return true or false. Items are included in the result when true and excluded when false. The presence of undefined seems to disrupt this process.
A more succinct syntax can be employed by utilizing an arrow function without curly braces.
For example:
return array.filter(el => el.length < 10);
If you introduce curly braces back into the equation (such as when your function spans multiple lines), the return statement must be explicitly provided.
For instance:
return array.filter(el => { return el.length < 10 });
The problem arises because the filter method in JavaScript requires a function that returns either true or false. Currently, the function you provided does not return anything, resulting in an undefined value (which is considered falsy). This leads to an empty array after filtering.
To fix this issue, you need to include a return statement inside the function passed to the filter method:
function validUserNames(array) {
return array.filter(function(el) { return el.length < 10 } );
}
Alternatively, you can use an arrow function without curly braces ({ and }) for implicit return:
function validUserNames(array) {
return array.filter(el => el.length < 10);
}
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