I'm trying to filter an array of strings
unfollow(handle: any) {
let following = this.user?.following || [];
following.filter((userHandle) => userHandle !== handle);
console.log(following);
}
I want to filter the array of following in user object but when I console.log(following) the array is unchanged. I tried different things including this this.user?.following?.filter((userHandle) => userHandle !== handle); but nothing is filtered out
You need to assign filtered output to someother variable. Filter will return the new array which contains filtered result
unfollow(handle: any) {
let following = this.user?.following || [];
let newArray = following.filter((userHandle) => userHandle !== handle);
console.log(newArray);
}
Array.filter returns a new array instead of mutating the existing one.
Try:
unfollow(handle: any) {
let following = this.user?.following || [];
let filtered = following.filter((userHandle) => userHandle !== handle);
console.log(filtered);
}
or without the optional chaining:
unfollow(handle: any) {
if (this.user) {
let following = this.user.following || [];
let filtered = following.filter((userHandle) => userHandle !== handle);
this.user.following = filtered
}
}
this.user?.following? If I try to do this this.user?.following = filtered I will get this error The left-hand side of an assignment expression may not be an optional property access.
this.user.following avoiding the ? optional chaining operator.As per documentation for Array.prototype.filter(),
The filter() method creates a new array with all elements that pass the test implemented by the provided function.
Therefore, you need to store the output of the filter() to use it anywhere else, including console.log().
let filtered = following.filter((userHandle) => userHandle !== handle);
this.user?.following = ["ronaldo", "messi"]then for example this user decides tounfollow("messi")so I simply want to update the array by filtering "messi" out