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import { isNothing } from "@jet/environment";
import { MetricsIdentifierType } from "../../foundation/metrics/metrics-identifiers-cache";
export function isFeatureEnabledForCurrentUser(objectGraph, rolloutRate) {
var _a;
if (rolloutRate <= 0.0) {
return false;
}
if (rolloutRate >= 1.0) {
// It is important that we not require a metrics ID when our rollout rate is 100%
return true;
}
const metricsIdString = (_a = objectGraph.metricsIdentifiersCache) === null || _a === void 0 ? void 0 : _a.getMetricsIdForType(MetricsIdentifierType.user);
if (isNothing(metricsIdString) || metricsIdString.length === 0) {
// if the user does not have a DSID, err on the side of caution.
return false;
}
if (metricsIdString.length < 2) {
// If we don't have enough characters to normalize, which should never happen, safely return false.
return false;
}
return normalizedMetricsIdLotteryValue(metricsIdString) < rolloutRate;
}
/**
* Gets a normalized value based on the metrics ID to match against the rollout rate to bucket a user.
* @param metricsId The user's metrics ID string
* @returns A value from 0.0 to 1.0 that we use to bucket the user
*/
function normalizedMetricsIdLotteryValue(metricsId) {
// Character mapping function that converts a character to its corresponding number.
// This value is guaranteed to be between 0 and 61, inclusive.
function charToNumber(char) {
const charCode = char.charCodeAt(0);
if (charCode >= 48 && charCode <= 57) {
// '0'-'9'
return 52 + charCode - 48;
}
else if (charCode >= 65 && charCode <= 90) {
// 'A'-'Z'
return 26 + charCode - 65;
}
else if (charCode >= 97 && charCode <= 122) {
// 'a'-'z'
return charCode - 97;
}
// This should never happen, if it does, the metrics ID is corrupt, but we rely on that not happening.
// This would indeed break the value guarantee.
return charCode;
}
// Extract the last two characters from the string.
const lastTwoChars = metricsId.slice(-2);
// Convert each of the last two characters to their respective number representation.
const num1 = charToNumber(lastTwoChars[0]);
const num2 = charToNumber(lastTwoChars[1]);
// Combine the two numbers into a single base-62 number.
const combinedValue = num1 * 62 + num2;
// Calculate the maximum possible value for two characters (each char has a value of 0 to 61, inclusive).
const maxValue = 61 * 62 + 61;
// Normalize the combined value to be between 0.0 and 1.0.
const normalizedValue = combinedValue / maxValue;
return normalizedValue;
}
//# sourceMappingURL=lottery.js.map
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