@replyke/express/dist/helpers/scoreEntity.js

Replyke: Build interactive apps with social features like comments, votes, feeds, user lists, notifications, and more.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.default = scoreEntity;
const date_fns_1 = require("date-fns");
const validateEntityDataForScoring = (entity) => {
    // Check `scoreUpdatedAt` validity
    if (!entity.scoreUpdatedAt) {
        console.error("Missing `scoreUpdatedAt` in entity.");
        throw new Error("Invalid entity: `scoreUpdatedAt` is required.");
    }
    // Check `createdAt` validity
    if (!entity.createdAt) {
        console.error("Missing or invalid `createdAt` in entity.");
        throw new Error("Invalid entity: `createdAt` is required.");
    }
    // Validate that `createdAt` is not in the future
    if (new Date(entity.createdAt) > new Date()) {
        console.error("`createdAt` is in the future:");
        throw new Error("Invalid entity: `createdAt` cannot be in the future.");
    }
    // Validate numerical fields
    if (!Array.isArray(entity.upvotes)) {
        console.error("Invalid `upvotes` field:", entity.upvotes);
        throw new Error("Invalid entity: `upvotes` must be an array.");
    }
    if (!Array.isArray(entity.downvotes)) {
        console.error("Invalid `downvotes` field:", entity.downvotes);
        throw new Error("Invalid entity: `downvotes` must be an array.");
    }
    if (typeof entity.repliesCount !== "number") {
        console.error("Invalid `repliesCount` field:", entity.repliesCount);
        throw new Error("Invalid entity: `repliesCount` must be a number.");
    }
    if (typeof entity.sharesCount !== "number") {
        console.error("Invalid `sharesCount` field:", entity.sharesCount);
        throw new Error("Invalid entity: `sharesCount` must be a number.");
    }
    // Validate `views`
    if (typeof entity.views !== "number" || entity.views <= 0) {
        console.error("Invalid `views` field:", entity.views);
        throw new Error("Invalid entity: `views` must be a positive number.");
    }
};
const GAP_IN_MINUTES_BETWEEN_RESCORING = 5;
function scoreEntity(entity) {
    validateEntityDataForScoring(entity);
    const currentStateReturn = {
        updated: false,
        newScore: entity.score,
        newScoreUpdatedAt: entity.scoreUpdatedAt,
    };
    // Validate `scoreUpdatedAt`
    if (entity.scoreUpdatedAt &&
        (0, date_fns_1.differenceInMinutes)(new Date(), new Date(entity.scoreUpdatedAt)) <=
            GAP_IN_MINUTES_BETWEEN_RESCORING) {
        return currentStateReturn;
    }
    const upvotesCount = entity.upvotes.length;
    const downvotesCount = entity.downvotes.length;
    const repliesCount = entity.repliesCount;
    const sharesCount = entity.sharesCount;
    const views = Math.max(entity.views, 1); // Ensure views is at least 1
    const createdAt = entity.createdAt;
    // Weight factors for different elements of the score
    const UPVOTE_WEIGHT = 1;
    const DOWNVOTE_WEIGHT = -0.5;
    const REPLY_WEIGHT = 0.5;
    const SHARE_WEIGHT = 2;
    // Base interaction score
    const interactionScore = UPVOTE_WEIGHT * upvotesCount +
        DOWNVOTE_WEIGHT * downvotesCount +
        REPLY_WEIGHT * repliesCount +
        SHARE_WEIGHT * sharesCount;
    // Base score for all posts, decays over time
    const BASE_SCORE = 2; // Starting score for new posts
    const HALF_LIFE = 48; // Half-life in hours for the base score decay
    // Calculate time since publication in hours
    const time_since_publication = (new Date().getTime() - new Date(createdAt).getTime()) / (3600 * 1000);
    // Calculate decay factor for the base score
    const base_decay = Math.exp(-time_since_publication / HALF_LIFE);
    // Adjust the base score with decay
    const baseAdjustedScore = BASE_SCORE * base_decay;
    // Adjust interaction score by views to normalize for exposure
    const exposureAdjustedScore = interactionScore / Math.log2(views + 1);
    // Combine base score and interaction score
    const final_score = Math.max(0, baseAdjustedScore + exposureAdjustedScore);
    return {
        updated: true,
        newScore: parseFloat(final_score.toFixed(2)),
        newScoreUpdatedAt: new Date(),
    };
}