Finding and replacing emojis...

doSomeRegex.js

var emojisUrl = "https://api.github.com/emojis"; // GitHub API for emoji mapping short name to URL of image
var ob = {}; //place holder for response, object keys short name to url of image
var re = /(\:\w+\:)(?=\s|[\!\.\?]|$)/gim;
var str = "dummy string to be replaced by text content of the markdown posts";
var ar = str.match(re); //array of occurences of values that match
var strAr = str.split(re); //array of string values, separated on matching occurences
strAr.forEach(function(curVal, i, array){
  var nwVal = ob[curVal];
  var tmpRe = new RegExp(curVal, 'gi');
  str.replace(str,nwVal);
});

handleEmojis.js

#!/usr/bin/env node

var util = require('util'),
    fs = require('fs'),
    request = require('request'),
    argv = require('minimist')(process.argv.slice(2)),
    filePath = argv._[0],
    imagePathPrefix = '/images/emoji/',
    emojisUrl = "https://api.github.com/emojis",
    emojisOb = {},
    options = {
      url: emojisUrl,
      headers: {
        'User-Agent': 'Awesome-Octocat-App'
      }
    },
    re = /(\:\w+\:)(?=\s|[\!\.\?]|$)/gim;

console.log('starting');

request(options, function (error, response, body) {
  if (!error && response.statusCode == 200) {
    var fCt = 0;
    var mCt = 0;
    emojisOb = JSON.parse(body);
    var fileNameAr = fs.readdirSync(filePath);
    for( var i=0; i<fileNameAr.length; i++ ){
        var curVal = filePath+fileNameAr[i];
        if( curVal.substr(-3) === '.md' ){
            var file = curVal;

            var contents = fs.readFileSync(file, 'utf-8');

            //fs.readFile(file, 'utf-8', function(err, contents){
                fCt++;
                if( re.test(contents) ){
                    console.log('match found in '+file);
                    mCt++;
                    var result = contents;
                    var foundMatch = false;
                    for( var prop in emojisOb ){
                        if( contents.indexOf(':'+prop+':') > -1 ){
                            foundMatch = true;
                            console.log('found a match for '+prop+' in '+file);
                            var nwRe = new RegExp(":"+prop+":","gi");
                            result = result.replace(nwRe, '<img src="'+imagePathPrefix+prop+'.png'+'" alt="'+prop+'" style="height:auto;width:21px;">');
                        }
                    }
                    if(foundMatch){
                        fs.writeFile(file, result, 'utf-8', function(er){
                            if(er){
                                console.log('error: '+er);
                            }else{
                                console.log('writing file back with updates')
                            }
                        });
                    }
                }
            //});
        }
    }
    console.log('found '+fCt+' .md files and '+mCt+' emoji short name occurrences');
  }else{
    console.log('error getting '+emojisUrl+', response status code: '+response.statusCode);
    console.log('nothing to do, exiting');
  }
});

console.log('done');

References.md

RegEx for matching short code emoji names (probably anything within colons). http://stackoverflow.com/questions/28077049/regex-matching-emoticons

Using a Node .js file as a shell executable: http://www.bennadel.com/blog/2329-building-executable-scripts-for-the-mac-osx-command-line-with-node-js.htm

RegEx 101: https://regex101.com/r/hI5qF5/1

test.js

#!/usr/bin/env node

var util = require('util'),
    fs = require('fs');

console.log('starting');

fs.readdir('./', function(err, files){
    console.log('searching for .md');
    files.filter(function(file){ return file.substr(-3) === '.md';  })
    .forEach(function(file){
        console.log('reading a .md file'+file);
    });
});

console.log('done');

testing.js

#!/usr/bin/env node

var emojisOb = require('./src/emojis.json');
var sampleUrl = "https://assets-cdn.github.com/images/icons/emoji/unicode/1f424.png?v5";

// console.log(String.fromCodePoint("0x1f37a"));
function getUni( key ){
	var url = emojisOb[key];
	if( null != url ){
		var tmpCode = extractEmojiUnicodeFromUrl(url);
		return "0x"+tmpCode;
	}else{
		return null;
	}
}
function extractEmojiUnicodeFromUrl( val ){
	var nwVal = val.split("unicode/")[1].split("?")[0].split(".png")[0];
	console.log("found a val: "+nwVal);
	return nwVal;
}
var myDrink = getUni("beers");
var o = String.fromCodePoint(myDrink);
console.log(o);

console.log("typeof: "+typeof o);

testScript.js

#!/usr/bin/env node

var util = require('util'),
    fs = require('fs'),
    // http = require('http'),
    emojisUrl = "http://api.github.com/emojis",
    emojisOb = {};

console.log('starting');

fs.readFile('./emojisResp.json', 'utf-8', function(err, data){
    if(err){
        console.log('error: '+err);
    } else {
        emojisOb = JSON.parse(data);
        console.log('got emojis master ob');
    }
});

var re = /(\:\w+\:)(?=\s|[\!\.\?]|$)/gim;

fs.readdir('./', function(err, files){
    console.log('searching for .md');
    files.filter(function(file){ return file.substr(-3) === '.md';  })
    .forEach(function(file){
        console.log('reading a .md file');
        fs.readFile(file, 'utf-8', function(err, contents){
            if( re.test(contents) ){
                var result = contents;
                var foundMatch = false;
                for( var prop in emojisOb ){
                    if( contents.indexOf(':'+prop+':') > -1 ){
                        foundMatch = true;
                        console.log('found a match for '+prop+' in '+file);
                        var nwRe = new RegExp(":"+prop+":","gi");
                        result = result.replace(nwRe, '<img src="'+emojisOb[prop]+'" alt="'+prop+'" style="height:auto;width:21px;">');
                    }
                }
                if(foundMatch){
                    fs.writeFile(file, result, 'utf-8', function(er){
                        if(er){
                            console.log('error: '+er);
                        }else{
                            console.log('writing file back with '+prop+' replaced as '+'!['+prop+']('+emojisOb[prop]+')')
                        }
                    });
                }
            }
        });
    });
});

console.log('done');