tctx/index.js

'use strict';

const csprng = require('@lukeed/csprng');

let IDX = 256, HEX = [];
for (; IDX--;)
    HEX[IDX] = (IDX + 256).toString(16).substring(1);
/*#__INLINE__*/
const to_hex = (arr) => {
    let i = 0, output = '';
    // @ts-ignore
    for (; i < arr.length; i++)
        output += HEX[arr[i]];
    return output;
};
/*
Anatomy of a Traceparent

00-4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-01
^  ^                                ^                ^
|  |                                |                |
|  |                                |                flags (2 hex)
|  |                                parent-id (16 hex)
|  trace-id (32 hex)
version (2 hex)
*/
const trace_id_size = 16;
const parent_id_size = 8;
const W3C_TRACEPARENT_VERSION = '00';
const sampled_flag = '00';
const traceparent = (version, trace_id, parent_id, flags) => ({
    version,
    trace_id,
    parent_id,
    flags,
    child() {
        return traceparent(this.version, this.trace_id, to_hex(csprng.random(parent_id_size)), this.flags);
    },
    toString() {
        return `${this.version}-${this.trace_id}-${this.parent_id}-${this.flags}`;
    },
});
const make = () => {
    const total_size = trace_id_size + parent_id_size;
    const id = csprng.random(total_size);
    return traceparent(W3C_TRACEPARENT_VERSION, to_hex(id.slice(0, trace_id_size)), to_hex(id.slice(trace_id_size, total_size)), sampled_flag);
};
const parse = (value) => {
    if (value.length > 55)
        return null;
    const segs = value.split('-');
    return traceparent(segs[0], segs[1], segs[2], segs[3]);
};

exports.make = make;
exports.parse = parse;