convert all psd files in a folder into png files

psd2png.js

// https://gist.github.com/xNok/74934a0c1c8500bfe84c8de6e92386cd
var PSD = require('psd');
var fs = require('fs');
 
// command usage validation
if (process.argv.length <= 2) {
    console.log("Usage: " + __filename + " path/to/directory/ path/to/output_dir/");
    process.exit(-1);
}
 
var path   = process.argv[2];
var output = process.argv.length >= 3 ? process.argv[3] : null;
 
fs.readdir(path, function(err, items) {
    for (var i=0; i<items.length; i++) {
        psd2png(path + items[i], output)
    }
});

function psd2png(input, output){
    String.prototype.replaceAll = function(search, replacement) {
        var target = this;
        return target.replace(new RegExp(search, 'g'), replacement);
    };

    String.prototype.basename = function() {
        var str = this;
        var base = new String(str).substring(str.lastIndexOf('/') + 1); 
            if(base.lastIndexOf(".") != -1)       
                base = base.substring(0, base.lastIndexOf("."));
        return base;
    };

    if ( output == null ){
        output = input.replaceAll("psd", "png");
    }else{
        output = output + input.basename() + ".png";
    }
    console.log("converting " + input + " to " + output)
    PSD.open(input).then(function (psd) {
      return psd.image.saveAsPng(output);
    }).then(function () {
      console.log("Finished!");
    });
}