linestat

linestat.js

import { createReadStream } from 'fs';

async function * splitLines(inputStream) {
    let carry = '';

    for await (const chunk of inputStream) {
        const lines = (carry + chunk).split('\n');
        carry = lines.pop();
        yield * lines;
    }

    if (carry !== '') {
        yield carry;
    }
}

async function main() {
    if (process.stdin.isTTY) {
        console.error("Pipe filenames into stdin");
        console.error("Ex: git ls-files '*.js' | node linestat");
        return;
    }

    const stats = [];
    let sloc = 0;

    process.stdin.setEncoding('utf-8');
    for await (const stdinLine of splitLines(process.stdin)) {
        const filename = stdinLine.trim();
        if (filename === '') {
            continue;
        }
        for await (const line of splitLines(createReadStream(filename))) {
            if (line.trim() === '') {
                continue;
            }
            const lineLength = line.trimEnd().replace(/^\t+/g, s => ' '.repeat(s.length * 4)).length;
            if (lineLength > 10000) {
                console.error(`Skipping the line of length ${lineLength} in ${filename}`);
                continue;
            }
            stats[lineLength] = (stats[lineLength] || 0) + 1;
            sloc++;
        }
    }
    for (let i = 0; i < stats.length; i++) {
        console.log(`${i}\t${stats[i] || 0}`);
    }
    console.error(`(${sloc} SLOC total)`);
}

main().catch(reason => {
    console.error(reason);
    process.exit(1);
})