linguist-js/dist/src/program/fs/readFile.js

Analyse the programming languages used in a folder or from raw content, using the same rules that GitHub Linguist does.

import FS from 'node:fs';
/**
 * Read part of a file on disc.
 * @throws 'EPERM' if the file is not readable.
 */
export default async function readFileChunk(filename, onlyFirstLine = false) {
    const chunkSize = 100;
    const stream = FS.createReadStream(filename, { highWaterMark: chunkSize });
    let content = '';
    for await (const data of stream) { // may throw
        content += data.toString();
        if (onlyFirstLine && content.includes('\n')) {
            return content.split(/\r?\n/)[0];
        }
    }
    return content;
}