Script used to generate data for https://twitter.com/zpao/status/998702031278768129

blame.js

// inspired by https://github.com/tj/git-extras/blob/master/bin/git-line-summary

const util = require("util");
const exec = util.promisify(require("child_process").exec);
const execSync = require("child_process").execSync;

const DIR = "/Users/poshannessy/FB/code/react-clean";
const REF = "origin/master";
const AUTHOR = "Paul O’Shannessy";
const PERIOD_DAYS = 1;

async function e(cmd, cwd) {
  const { stdout, stderr } = await exec(cmd, { cwd: cwd });
  return stdout.trim();
}
function eSync(cmd, cwd) {
  let stdout = execSync(cmd, { cwd: cwd, encoding: "utf8" });
  return stdout.trim();
}

async function git(cmd) {
  return await e(`git ${cmd}`, DIR);
}

function formatDate(d) {
  return `${d.getFullYear()}-${d.getMonth() + 1}-${d.getDate()}`;
}

function getStartNextMonth(d) {
  let rv = new Date(d);
  rv.setMonth(d.getMonth() + 1, 1);
  rv.setHours(0, 0, 0, 0);
  return rv;
}

function getEndMonth(d) {
  let rv = new Date(d);
  rv.setMonth(d.getMonth() + 1, 0);
  rv.setHours(23, 59, 59, 999);
  return rv;
}

async function main() {
  await git(`checkout ${REF}`);
  let firstCommit = await git("rev-list --max-parents=0 HEAD");
  let firstCommitTimestamp = await git(`show -s --format=%cI ${firstCommit}`);
  let firstCommitDate = new Date(firstCommitTimestamp);
  // firstCommitDate.setDate(firstCommitDate.getDate() - 1);
  let lastCommitTimestamp = await git(`show -s --format=%cI ${REF}`);
  let lastCommitDate = new Date(lastCommitTimestamp);
  lastCommitDate.setDate(lastCommitDate.getDate() + 1);

  let workingDate = new Date(firstCommitDate);
  workingDate.setHours(0, 0, 0, 0);

  console.log(firstCommit, firstCommitDate);
  console.log(REF, lastCommitDate);

  let commitsByDate = new Map();

  await git(`checkout ${REF}`);

  while (workingDate < lastCommitDate) {
    // let endDate = new Date(workingDate);
    // endDate.setDate(endDate.getDate() + PERIOD_DAYS);
    let endDate = getEndMonth(workingDate);

    let dayCommitRaw = await git(
      `log --no-merges --since='${workingDate.toISOString()}' --until='${endDate.toISOString()}' --format='%H %cI' --reverse | head -n1`
    );

    let [dayCommit, dayCommitTimestamp] = dayCommitRaw.split(" ");

    console.log(`${workingDate.toISOString()} - ${endDate.toISOString()}`);

    if (dayCommit !== "") {
      commitsByDate.set(new Date(dayCommitTimestamp), dayCommit);
    }
    // workingDate = endDate;
    workingDate = getStartNextMonth(workingDate);
  }

  for (let [commitDate, commitSHA] of commitsByDate) {
    await git(`checkout ${commitSHA}`);
    let totalCount = 0;
    let blameCount = 0;

    let files = await git("ls-files");
    files = files
      .split("\n")
      .map(s => s.trim())
      .filter(f => {
        try {
          let typeText = eSync(`file ${f} | grep text`, DIR);
          return typeText !== "";
        } catch (e) {
          return false;
        }
      });

    for (file of files) {
      let lines = await e(`wc -l ${file}`, DIR);
      lines = parseInt(lines);
      totalCount += lines;
      let blameLines = await e(
        `git blame --line-porcelain ${file} | grep "^author\ " | LC_ALL=C sed -n 's/^author //p' | grep '${AUTHOR}' | wc -l`,
        DIR
      );
      blameLines = parseInt(blameLines);
      blameCount += blameLines;
    }

    console.log(`${formatDate(commitDate)}\t${totalCount}\t${blameCount}`);
  }
}

try {
  main();
} catch (e) {
  console.error(e);
}