function to rate a vs b in javascript

Here is an example function that can be used to rate A vs B in JavaScript:

index.tsx
function rateAvsB(aRating, bRating) {
  // Calculate the expected probability of A winning
  let expectedProbabilityA = 1 / (1 + Math.pow(10, (bRating - aRating) / 400));
  
  // Calculate the actual outcome of A vs B
  let actualOutcomeA = 1; // 1 = A wins, 0 = B wins
  
  // Calculate the new rating for A based on the outcome
  let newRatingA = aRating + 32 * (actualOutcomeA - expectedProbabilityA);
  
  return newRatingA;
}
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This function uses the Elo rating system to calculate the new rating of A after playing against B. The ratings are expressed as numbers, and the higher the rating is, the better the player is. The function takes the current ratings of A and B as input, and returns the new rating of A after playing against B.

To use this function, simply call it with the ratings of A and B:

index.tsx
let aRating = 1500;
let bRating = 1600;

let newARating = rateAvsB(aRating, bRating);

console.log("A's new rating is: " + newARating);
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In this example, A's current rating is 1500, and B's current rating is 1600. After playing against each other, A's new rating is calculated using the rateAvsB function, and the result is printed to the console.