trouble turning file into array and then outputting object value

Question

The goal of my application is simple:

• Accept a random number parameter
• Read the dictionary.txt file
• turn that file into an array by taking each word in the file (each word is on a new line in the file)
• push each array item created into an object and then have itself as a word property

At the point I have the object created, my aim is to get a random word from that object, for example:

outputObj[randNum].word

Which should return the word at the index I set in the randNum parameter and the value stored in its word property.

I am getting confused and have tried everything I can think of to achieve the end result.

Here is my current JS:

var fs = require('fs),
    getWordFromRandomNumber = function(randNum) {
        var output = fs.readFileSync('../dictionary/dictionary.txt', 'utf8')
            .trim()
            .split('\r\n')
            .map(line => line.split('\r\n'))
            .reduce(function(outputObj, line){
            outputObj[line] =  outputObj[line] || [];
            outputObj[line].push({
                word: line,
            });
            return outputObj[randNum].word;
        }, {});


        console.log(JSON.stringify(output, null, 2));
    }

getWordFromRandomNumber(25);

I expect this to return to me the value of outputObj[25].word but all I get is a cascade of the whole file, see here (note I am using my cmd to run the file using babel and node with the command "babel wordGenerator.js | node":

Any help would be much appreciated as I am all out of ideas at the moment.

Thanks, SD

Answer 1

If the file really has all individual words on a new line (your output suggests something else) then the following should suffice:

var output = fs.readFileSync('../dictionary/dictionary.txt', 'utf8')
  .trim() // to remove whitespace
  .split('\r')   // creates array with individual words
  .map(item => { return { word :item } }); // creates array with objects
return output[randNum % output.length].word;

No need to do reduce or create another outobject.

This code should work with valid input, where words are separated by '\r'. The output suggest words are separated by '\r\n' or '\r\'. This creates words with '\r'. If you want words without '\r', you should apply some regex to flush that out. Maybe change into .split(/\r\n|\r|\n/g); will do the trick.

PS: the % part is to ensure that if randNum input is larger than the array length, you do not get error output. Array is created inside the function, so when called, it is still unclear what the maximum valid number actually will be.

Answer 2

One solution possible :

var str = " line_0\r\nline_1\r\nline_2\r\nline_3\r\nline_4\r\nline_5\r\nline_6\r\nline_7\r\nline_8\r\nline_9\r\nline_10\r\nline_11\r\nline_12\r\nline_13\r\nline_14\r\nline_15\r\nline_16\r\nline_17\r\nline_18\r\nline_19\r\nline_20\r\nline_21\r\nline_22\r\nline_23\r\nline_24\r\nline_25\r\nline_26\r\nline_27\r\nline_28\r\nline_29\r\nline_30\r\nline_31\r\nline_32\r\nline_33\r\nline_34\r\nline_35\r\nline_36\r\nline_37\r\nline_38\r\nline_39\r\nline_40\r\nline_41\r\nline_42\r\nline_43\r\nline_44\r\nline_45\r\nline_46\r\nline_47\r\nline_48\r\nline_49\r\nline_50\r\nline_51\r\nline_52\r\nline_53\r\nline_54\r\nline_55\r\nline_56\r\nline_57\r\nline_58\r\nline_59\r\nline_60\r\nline_61\r\nline_62\r\nline_63\r\nline_64\r\nline_65\r\nline_66\r\nline_67\r\nline_68\r\nline_69\r\nline_70\r\nline_71\r\nline_72\r\nline_73\r\nline_74\r\nline_75\r\nline_76\r\nline_77\r\nline_78\r\nline_79\r\nline_80\r\nline_81\r\nline_82\r\nline_83\r\nline_84\r\nline_85\r\nline_86\r\nline_87\r\nline_88\r\nline_89\r\nline_90\r\nline_91\r\nline_92\r\nline_93\r\nline_94\r\nline_95\r\nline_96\r\nline_97\r\nline_98\r\nline_99 ";

var arr = str
           .trim()
           .split("\r\n")
           .map(function(value , index){
             return { index: index , word : value}; 
           });


var len = arr.length;
var randNum = Math.floor(Math.random() * len);

var result = arr[ randNum ].word;

document.body.innerHTML+= '<br> randNum = ' + randNum + ' result : ' + result ;

Just click run again and again . . .

---

So your code become :

var fs = require('fs),
    getWordFromRandomNumber = function(randNum) {
        var output = fs.readFileSync('../dictionary/dictionary.txt', 'utf8')
           .trim()
           .split('\r\n')
           .map( val => { return {  word : val }; });

       console.log(JSON.stringify(output, null, 2));
       return output[ randNum ].word;
   };

getWordFromRandomNumber(25);

Note that each time you call getWordFromRandomNumber you will read the dictionary file , split it , map it !
If your dictionary is static maybe you can 'cache' the result of process !

var fs = require('fs),
    cached = null ,
    getWordFromRandomNumber = function(randNum) {

       if(cached) return cached[ randNum ].word;

       var output = fs.readFileSync('../dictionary/dictionary.txt', 'utf8')
           .trim()
           .split('\r\n')
           .map( val => { return {  word : val }; });

       console.log(JSON.stringify(output, null, 2));
       cached = output;
       return output[ randNum ].word;
   };

getWordFromRandomNumber(25);

Answer 3

I have my application working perfect now, the issue was fixed by using ajax instead of nodes fs.

Now I have this:

var getDictionaryFile = function(file) {
    var xhr = new XMLHttpRequest();
    xhr.open("GET", file, false);
    xhr.send(null);
    var returnValue = xhr.responseText;
    return returnValue;
},
getWordFromRandomNumber = function(randNum, el) {  
        var target = document.querySelectorAll(el),
            output = getDictionaryFile("../dictionary/dictionary.txt")
        .trim()
        .split('\r\n');

        [].forEach.call(output, function(line) {
            if(output[randNum % output.length - 1] == line ){
                [].forEach.call(target, function(element) {
                    element.innerHTML = line;
                });
            }
        });

    }

And the response text is doing the same thing as the last code except working, ie: being read, split into an array, looped over and then the index I want is decided by a random number. Thus, I get a random word with each request as expected.