A Parser for D&D Beyond Random Tables

randomtableparser.js

///////////////////////////////////////////////////////////////////////////////

// example from https://www.dndbeyond.com/sources/xgte/character-names
// let id = 'f0edbf90-4ecc-4a4e-9f3f-17f0b154e25f';

const getRandomTable = function(id) {

    // src: https://stackoverflow.com/questions/3895478/
    const range = (size, startAt = 0) => [...Array(size).keys()].map(i => i + startAt);
    
    const getDiceRoller = (s) => () => {
        const count = +(s.split('d')[0] || 1);
        const sides = +s.split('d')[1];
        return range(count)
            .map(() => Math.floor(Math.random() * sides + 1))
            .reduce((a, b) => a + b);
    };

    const table = document.querySelector(`[data-content-chunk-id="${id}"]`);

    const header = [...table.querySelectorAll('thead tr th')]
        .map(th => th.innerText);
        
    const diceRoll = getDiceRoller(header[0]);

    const body = [...table.querySelectorAll('tbody tr')]
        .map(tr => [...tr.querySelectorAll('td')].map(td => td.innerText)
        );
    
    const results = [];
    body.forEach(r => {
        const roll = r[0];
        const result = r.slice(1);
        if(roll.includes('–')) {
            const [start, end] = roll.replace('00', '100').split('–').map(n => +n);
            range(end-start+1, start).forEach(i => {
                results[i] = result;
            });
        } else {
            results[+roll] = result;
        }
    });

    const roll = () => results[diceRoll()];

    return {
        table,
        header,
        body,
        results,
        roll,
    }    

};