utils/src/csv.ts
ztimson a03567eba3
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toCSV comma fix
2025-04-06 21:37:01 -04:00

89 lines
2.9 KiB
TypeScript

import {makeArray} from './array.ts';
import {ASet} from './aset.ts';
import {dotNotation, flattenObj, JSONSanitize} from './objects.ts';
import {LETTER_LIST} from './string.ts';
/**
* Parse a CSV string into an array of objects
*
* @param csv String with CSV
* @param hasHeaders First line of CSV contains headers
* @return {T[]} Array of parsed objects
*/
export function fromCsv<T = any>(csv: string, hasHeaders = true): T[] {
function parseLine(line: string): (string | null)[] {
const columns: string[] = [];
let current = '', inQuotes = false;
for (let i = 0; i < line.length; i++) {
const char = line[i];
const nextChar = line[i + 1];
if (char === '"') {
if (inQuotes && nextChar === '"') {
current += '"'; // Handle escaped quotes
i++;
} else inQuotes = !inQuotes;
} else if (char === ',' && !inQuotes) {
columns.push(current.trim()); // Trim column values
current = '';
} else current += char;
}
columns.push(current.trim()); // Trim last column value
return columns.map(col => col.replace(/^"|"$/g, '').replace(/""/g, '"'));
}
// Normalize line endings and split rows
const rows = [];
let currentRow = '', inQuotes = false;
for (const char of csv.replace(/\r\n/g, '\n')) { // Normalize \r\n to \n
if (char === '"') inQuotes = !inQuotes;
if (char === '\n' && !inQuotes) {
rows.push(currentRow.trim()); // Trim row
currentRow = '';
} else currentRow += char;
}
if (currentRow) rows.push(currentRow.trim()); // Trim last row
// Extract headers
let headers: any = hasHeaders ? rows.splice(0, 1)[0] : null;
if (headers) headers = headers.match(/(?:[^,"']+|"(?:[^"]|"")*"|'(?:[^']|'')*')+/g)?.map((h: any) => h.trim());
// Parse rows
return <T[]>rows.map(r => {
const props = parseLine(r);
const h = headers || (Array(props.length).fill(null).map((_, i) => {
let letter = '';
const first = i / 26;
if (first > 1) letter += LETTER_LIST[Math.floor(first - 1)];
letter += LETTER_LIST[i % 26];
return letter;
}));
return h.reduce((acc: any, h: any, i: number) => {
dotNotation(acc, h, props[i]);
return acc;
}, {});
});
}
/**
* Convert an array of objects to a CSV string
*
* @param {any[]} target Array of objects to create CSV from
* @param {boolean} flatten Should nested object be flattened or treated as values
* @return {string} CSV string
*/
export function toCsv(target: any, flatten=true) {
const t = makeArray(target);
const headers = new ASet(t.reduce((acc, row) => [...acc, ...Object.keys(flatten ? flattenObj(row) : row)], []));
return [
headers.join(','),
...t.map(row => headers.map((h: string) => {
const value = dotNotation<any>(row, h);
if(value == null) return '';
if(typeof value == 'object') return `"${JSONSanitize(value).replaceAll('"', '""')}"`;
if(typeof value == 'string' && /[\n",]/g.test(value)) return `"${value.replaceAll('"', '""')}"`;
return value;
}).join(','))
].join('\n');
}