Hexo use modified date from git commit log

modified_date.js

const childProcess = require('child_process');

/**
 * use `page.modified` in your theme
 */
hexo.extend.filter.register('before_post_render', function (data) {
    data.title = data.title.toLowerCase();
    data.modified = git_log(data.full_source)
    return data;
});

function git_log(dir) {
    // https://git-scm.com/docs/pretty-formats
    var args = [
        'log',
        '--name-only',
        '--pretty=format:"%as"',
        '-n',
        '1',
        dir
    ];
    var s = childProcess.execFileSync("git", args).toString();
    return s.split('\n')[0];
}