I'm looking for a javascript function that compares two strings in a "standard" way, or at least in the same way it does in dart.
I have this code in dart that give two strings it checks which is the largest and creates a single string separated by a "-" with the largest string in front.
//dart code
void main() {
String currentUserId = "bbijdF7zKgR7jOIAs7Ka86jwdRu1";
String peerId = "UVvUo4xCM4N4TtiFWL5B6vOFzN53";
String groupChatId = "";
if (currentUserId.compareTo(peerId) > 0) {
groupChatId = '$currentUserId-$peerId';
} else {
groupChatId = '$peerId-$currentUserId';
}
print(groupChatId);
}
The print will return bbijdF7zKgR7jOIAs7Ka86jwdRu1-UVvUo4xCM4N4TtiFWL5B6vOFzN53
So far no problem.
Now I should replicate this code in javascript and I found the localeCompare link function which should do the same thing as compareTo() link in dart. But this is not the case since, in the case of the two strings, they have different results.
//js code
var currentUserId = "bbijdF7zKgR7jOIAs7Ka86jwdRu1";
var peerId = "UVvUo4xCM4N4TtiFWL5B6vOFzN53";
var groupChatId = "";
if (currentUserId.localeCompare(peerId) > 0) {
groupChatId = `${currentUserId}-${peerId}`
} else {
groupChatId = `${peerId}-${currentUserId}`
}
console.log(groupChatId)
The print will return UVvUo4xCM4N4TtiFWL5B6vOFzN53-bbijdF7zKgR7jOIAs7Ka86jwdRu1
There are rare cases in which they give two different results, but this is precisely the problem. Is there any function in javascript that behaves like the compareTo in dart?
If anyone could explain to me why these two functions sometimes differ in the result I would be very grateful
In Dart, compareTo sorts the string by the character's code point but when using localeCompare the strings are compared in lexicographic order based on the user's current language. Additionally, the result from localeCompare may not be consistent between users with different locale settings.
A better way to compare your strings would be to add them to an array and .sort() them. This also orders by code point and will be consistent regardless of the user's locale setting. However, since you want the lower value string first you will need a custom sorting function to handle this.
Then, instead of using string literals to combine, just .join() the array with the - character.
let userId = "bbijdF7zKgR7jOIAs7Ka86jwdRu1";
let peerId = "UVvUo4xCM4N4TtiFWL5B6vOFzN53";
let chatId = [userId, peerId].sort(
new Intl.Collator('en', { caseFirst: 'lower' }).compare
).join('-');
console.log(chatId);This has proven to be surprisingly difficult. Hopefully this solution behaves as you expect in all circumstances.