is there a open source c# library with a gethashcode equivalent which is even faster than gethashcode() for strings? in csharp in javascript

Yes, there is an open-source library for C# called CityHash.NET which provides a hashing algorithm similar to GetHashCode() but faster for strings. CityHash was developed by Google and has been optimized for use on modern processors. It is available as a NuGet package and can be easily integrated into your C# project.

Here's an example of how to use it:

index.tsx
using Google.CityHash;

string inputString = "some string to hash";
ulong hashValue = CityHash.CityHash64(inputString, inputString.Length);
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In JavaScript, one such library which provides faster hashing is MurmurHash3. It is available as a npm package and can be easily integrated into your project. Here's an example of how to use it:

index.tsx
const MurmurHash3 = require('murmurhash3');

let inputString = 'some string to hash';
let hashValue = MurmurHash3.x64.hash128(inputString, 0);
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Note that hashing algorithms are not designed to be reversible, and the probability of two different inputs producing the same hash value (a collision) cannot be entirely avoided. Therefore, it is important to choose the appropriate hashing algorithm based on the specific requirements and constraints of your project.