hexo-filter-date-from-git/index.js

Read git log and overwrite the front-matter properties `date` and `updated` for each posts

/* global hexo */
/* eslint no-param-reassign:0, strict:0 */

'use strict';

const log = hexo.log || log.log;
const path = require('path');
const execSync = require('child_process').execSync;
const moment = require('moment-timezone');
const front = require('hexo-front-matter');

hexo.extend.filter.register('before_post_render', data => {
  const filePath = getFilePath(data);
  const [originalDate, originalUpdated] = getOriginalDateMeta(data)

  if (!originalDate || originalDate.valueOf() <= 1000) {
    // original "date" is invalid
    data.date = getDate(filePath);
    log.log(`Post ${filePath}  set "date" to ${data.date.format('YYYY-MM-DD HH:mm:ss')}`);
  }
  if (!originalUpdated || originalUpdated.valueOf() <= 1000) {
    // original "updated" is invalid
    data.updated = getUpdated(filePath);
	  log.log(`Post ${filePath}  set "updated" to ${data.updated.format('YYYY-MM-DD HH:mm:ss')}`);
  }

  return data;
});

function getDate(filePath) {
  const date = execSync(`git log --follow --format="%ad" -- "${filePath}" | tail -1`).toString().trim();
  // If the file is created a moment ago, it will be an untracked file, then git can not log it
  if (date === '') {
    return moment();
  }
  return moment(new Date(date));
}

function getUpdated(filePath) {
  const updated = execSync(`git log --follow -1 --format="%ad" -- "${filePath}"`).toString().trim();
  if (updated === '') {
    return moment();
  }
  return moment(new Date(updated));
}

function getFilePath(data) {
  return path.resolve(hexo.config.source_dir, data.source);
}

function getOriginalDateMeta(data) {
  const frontMatter = front.parse(data.raw);
  if (frontMatter == null)
    return [null, null]
  return [frontMatter.date, frontMatter.updated]
}