csv.js

// crude, primitive module for tackling CSVs
// use something better i beg

const parseCSV = (text, delimiter = ",") => {

    // extract column headers
    const firstNewline = text.indexOf("\n");
    const columns = text.slice(0, firstNewline).split(delimiter);

    // read
    let curPart = "";
    let curColumn = 0;
    let quote = false, escapeQuote = false;
    let curRow = {};
    let result = [];

    for(let i = firstNewline + 1; i < text.length; i++) {
        
        const char = text[i];

        // handle terminators
        if(!quote && (char === delimiter || char === '\n')) {
            curRow[columns[curColumn]] = curPart;
            curPart = "";
            curColumn++;
            if(char === '\n') {
                result.push(curRow);
                curRow = {};
                curColumn = 0;
            }
            continue;
        }
        
        // handle quotes
        if(char === '"') {
            if(escapeQuote) {
                escapeQuote = false;
            } else if(quote && text[i + 1] === '"') {
                escapeQuote = true;
                continue;
            } else {
                quote = !quote;
                continue;
            }
        }

        curPart += char;

    }

    return result;

};

const exportCSV = (rows, delimiter = ",") => {

    const columns = [];
    for(const row of rows) {
        for(const col in row) {
            if(!columns.includes(col)) {
                columns.push(col);
            }
        }
    }

    return [columns.join(delimiter), ...rows.map(row => columns.map(col => {
        const str = String(row[col] ?? "");
        if(str.includes('"') || str.includes(delimiter)) return '"' + str.replace(/"/g, '""') + '"';
        return str;
    }).join(delimiter))].join("\n");

};

module.exports = {parseCSV, exportCSV};