crypto_solution.js

//SOLUTION 1) 

   Array.prototype.each_slice = function (size, callback){
        console.log(this.length, 'Size', size, 'Callback', callback);
        for (var i = 0, l = this.length; i < l; i += size){
            callback.call(this, this.slice(i, i + size));
        }
    };

    var Crypto = function(secretMessage){
        this.message = secretMessage;
    };

    Crypto.prototype.normalizePlainText = function(){
        var result = _.filter(this.message, function(message){
            return message.search(/[a-z]+/) == 0;
        })
        return result;
    }

    Crypto.prototype.setSegments = function(){
        var segmentLength = Math.ceil(Math.sqrt(this.normalizePlainText().length)); 
        var segments = [];
        this.normalizePlainText().each_slice(segmentLength, function(segment){
            segments.push(segment);
        })
        return segments;
    }

    Crypto.prototype.cipher = function(){
        cipher_array = []
        _.each(this.setSegments(), function(segment){
            _.each(segment, function(letter, index){
                cipher_array[index] = cipher_array[index] || []
                cipher_array[index].push(letter);
            });
        })
        _.map(cipher_array, function(array){
            return array.join('')
        }).join('');
    }


    var crypto1 = new Crypto('this is a secret message');
    crypto1.normalizePlainText();
    crypto1.cipher();
    
    
    
    // SOLUTION 2)
    
    Array.prototype.each_slice = function (size, callback){
        console.log(this.length, 'Size', size, 'Callback', callback);
        for (var i = 0, l = this.length; i < l; i += size){
            callback.call(this, this.slice(i, i + size));
        }
    };
    
    var Crypto = function(secretMessage){
        this.message = secretMessage;
        this.plainText = this.normalizePlainText();
        this.segments = this.setSegments();
        this.ciperText = this.cipher();
    };

    Crypto.prototype.normalizePlainText = function(){
        var result = _.filter(this.message, function(message){
            return message.search(/[a-z]+/) == 0;
        })
        return result;
    }

    Crypto.prototype.setSegments = function(){
        var segmentLength = Math.ceil(Math.sqrt(this.plainText.length)); 
        var segments = [];
        this.plainText.each_slice(segmentLength, function(segment){
            segments.push(segment);
        })
        return segments;
    }

    Crypto.prototype.cipher = function(){
        cipher_array = []
        _.each(this.segments, function(segment){
            console.log(segment);
            _.each(segment, function(letter, index){
                cipher_array[index] = cipher_array[index] || []
                cipher_array[index].push(letter);
            });
        })
        this.cipherText = _.map(cipher_array, function(array){
            return array.join('')
        }).join('');
    }


    var crypto1 = new Crypto('this is a secret message');