modules/chart_engine/static/lib/chart_utils/random.js

// Deterministic pseudo-random helpers for stable D3 renders.
(function (root) {
    const chartUtils = root.chartUtils;
    const random = chartUtils.random;

    random.hashString = value => {
        let hash = 2166136261;
        const text = String(value == null ? "" : value);
        for (let i = 0; i < text.length; i++) {
            hash ^= text.charCodeAt(i);
            hash = Math.imul(hash, 16777619);
        }
        return hash >>> 0;
    };

    random.seed = (jsonData, salt = "") => {
        const data = jsonData && jsonData.data ? jsonData.data : {};
        const columns = Array.isArray(data.columns) ? data.columns : [];
        const rows = Array.isArray(data.data) ? data.data : [];
        return random.hashString([
            salt,
            jsonData && jsonData.name,
            jsonData && jsonData.chart_name,
            rows.length,
            JSON.stringify(columns.map(column => [
                column && column.name,
                column && column.role,
                column && column.data_type,
            ])),
        ].join("|"));
    };

    random.generator = (jsonDataOrSeed, salt = "") => {
        let state = typeof jsonDataOrSeed === "number"
            ? jsonDataOrSeed >>> 0
            : random.seed(jsonDataOrSeed, salt);
        return () => {
            state = (state + 0x6D2B79F5) >>> 0;
            let t = state;
            t = Math.imul(t ^ (t >>> 15), t | 1);
            t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
            return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
        };
    };

    random.value = (jsonData, salt = "") => random.generator(jsonData, salt)();

    random.id = (jsonData, salt = "") => random.seed(jsonData, salt).toString(36);
})(globalThis);