print_subheading_search_result_content_to_md.js

/* 
NOTE: this requires node.js to be installed. 

the following script, when run from a single directory, will search all .md files in that directory and create a .md file containing all contents of a level 2 heading, like so:

    # Title
    ## Reflections
    * content1
    * content2
    ## Heading 2

As currently written, it will return 

    * content1
    * content2

but it should be pretty straightfoward to change your search term. Note that it should still work even if you don't have a ## Heading 2. 
If you'd like to see the actual filenames that the content is coming from, uncomment line 53
*/ 

var path = require('path'), fs=require('fs');
let output_randomnumber = Math.floor(Math.random() * 100000000);

function fromDir(startPath,filter,callback){

    console.log('Starting from dir '+startPath+'/');

    if (!fs.existsSync(startPath)){
        console.log("no dir ",startPath);
        return;
    }
    fs.writeFile('output_' +output_randomnumber+ '.md', '', (err) => { 
        if (err) throw err; 
    })
    var files=fs.readdirSync(startPath);
    for(var i=0;i<files.length;i++){
        var filename=path.join(startPath,files[i]);
        var stat = fs.lstatSync(filename);
        if (stat.isDirectory()){
            fromDir(filename,filter,callback); //recurse
        }
        else if (filter.test(filename)) callback(filename);
    };
};

fromDir(__dirname,/\.md$/i,function(filename){
    var data;
    try {
      data = fs.readFileSync(filename, 'utf8')
      function matchString()  {
        var result = data.match(/## Reflections\n(?<group_name>(?:.|\n)*?)(?:##|$)/);
        if (result !== null) {
        //  console.log('-- found: ',filename);
          console.log(result.groups.group_name);
            console.log ('added to filename: output_' +output_randomnumber)
            fs.appendFile('output_' +output_randomnumber+ '.md', result.groups.group_name, (err) => { 
                if (err) throw err; 
            })}           
     }
    matchString();
    } catch (err) {
      console.error(err)
    }
});

/* 
This piece of javascript will let you search the markdown files in a directory for a recurringly-used subheading 
(e.g. ## Goals or ## Todo in your daily notes) and then concatenate all of the pieces underneath of that specific heading 
into a markdown file with a randomly-generated-numerical identifier. I hope to turn this into a plugin one day (with schnazzy features), 
but for right now, I think it's useful enough that someone in the community might get something out of it. 
The script itself is here: https://github.com/eleanorkonik/js_projs/blob/main/projone/print_subheading_search_result_content_to_md.js and 
that github directory includes every heavily-commented, iterated step of how I got from "never made a program of any kind in my life" 
to "created a working javascript program" so if you're curious what each part of the code does, just navigate the directory. 
I'm happy to answer questions but please use at your own risk (backups are your friend!) because I'm not sure the error handling is particularly
robust and I am a very neophyte coder (although I had some experienced people help me make it, and as long as you don't habitually name your files 
outout_randomnumber it shouldn't be able to overwrite anything you care about). Shoutouts to @liam @koala54 @death_au and @simonthefox for the help.
*/