Search node js array for partial match with variable, return index or value

Question

Hello all I'm new to node and js - trying to make a small bot for a small discord channel , I've kinda hit a wall and can't find a solution.

I am trying to store user input data and recall it later. So far I have this to store the data as a json file.

data[user_id] = value_set
var out_data = JSON.stringify(data);
fs.writeFile('users.json', out_data);

And would look like this:

{"35978432146597841":"String.1","32146879124653147":"String.2"}

Now I want to recall the String.X value later based on the user's id. And this is where I am stuck. I figured I'd need to read the json file and transfer it to an array.

I think I successfully made it an array with the following:

var in_data = fs.readFileSync('users.json');
var data = JSON.parse(in_data);

var arr = []
for(var i in data){
arr.push([i, data [i]]);}

As... console.log(arr[1]);

shows: ['32146879124653147','String.2']

But I cannot figure out how to search that array by the user's id (user_id) to either locate the index and then split the value or even better just pull the value.

Everything I have tried to find the 'String.X' by the user_id has has failed. So what do I need to do to pull 'String.2' if I only know '32146879124653147'.

Any help will be appreciated. Thanks.

SOLUTION

var fs = require("fs");
var in_data = fs.readFileSync('users.json');
var data = JSON.parse(in_data);
var arr = [];

for(var i in data){
    arr.push({
            User:i,
            Input:data [i]
            });
        }
var value = arr.find(x => x.User === id);
var f_value = value.Input;
console.log(f_value);

OR

const userfile = require("./users.json");
var f_value = userfile[userID];

khaos11 · Accepted Answer · 2017-10-21 20:18:18Z

1

After much help from Jay this is the answer I came up with.

var fs = require("fs");
var in_data = fs.readFileSync('users.json');
var data = JSON.parse(in_data);
var arr = [];

for(var i in data){
    arr.push({
            User:i,
            Input:data [i]
            });
        }
var value = arr.find(x => x.User === userID);
var f_value = value.Input;
console.log(f_value);

OTHER

I have since found an easier way to accomplish the above, without fs, or creating an array.

const userfile = require("./users.json");
var f_value = userfile[userID];

edited Oct 21, 2017 at 20:18

answered Oct 13, 2017 at 2:46

khaos11

631 silver badge7 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Ashim Paul · Accepted Answer · 2017-10-12 22:05:06Z

0

You need to push the items separately and then loop over it skipping by 2 elements in the array.

var fs = require("fs");

var in_data = fs.readFileSync('users.json');
var data = JSON.parse(in_data);

var arr = []
for(var i in data){
  arr.push(i);
  arr.push(data[i]);
}

console.log("Printing arr...");
  for(var i=0; i<arr.length; i++) {
    console.log("arr[" + i + "]= " + arr[i]);
  }

  // Check if 32146879124653147 is found

  console.log("Checking 32146879124653147...");
  for (var i=0; i<arr.length; i+=2) {

    if (arr[i] === "32146879124653147") {
      console.log("Found " + arr[i+1]);
    }
  }

edited Oct 12, 2017 at 22:05

answered Oct 12, 2017 at 21:48

Ashim Paul

1002 bronze badges

3 Comments

khaos11 Over a year ago

Thanks for the answer, I am probably reading it wrong but the above looks like you need to know the string value. But that will be unknown and is what the user is storing. I will only know the users ID and will be using that to find the data they stored.

Ashim Paul Over a year ago

Changed it based on user ID value.

khaos11 Over a year ago

The first for loop works and prints out each array. Printing arr... arr[0]= 35978432146597841,String.1 arr[1]= 32146879124653147,String.2 and continues to Checking 32146879124653147... but then it stops nothing is printed after. If instead of console.log("Found " + arr[i+1]); I do var value = arr[i+1] console.log(value); it prints undefined.

Jay Hamilton · Accepted Answer · 2017-10-13 01:34:55Z

0

You can use find(). In your example, it will return the first key/value that matches, or undefined if there is no match.

var in_data = fs.readFileSync('users.json');
var data = JSON.parse(in_data);

let obj = {}
for(var i in data){

obj[i]:data [i];

let value = obj.find(value => id)
//if id = '32146879124653147' 
// then the 32146879124653147: 'String.2' key/value would be returned

edited Oct 13, 2017 at 1:34

answered Oct 12, 2017 at 21:38

Jay Hamilton

1145 bronze badges

5 Comments

khaos11 Over a year ago

Maybe I'm doing something wrong, but let value = arr.find(value => id) is only returning the first part of the array. So arr[0]. Even for troubleshooting purpose I manually type in value = arr.find(value => '32146879124653147'), it is not returning ['32146879124653147','String.2'] it is returning ['35978432146597841',"String.1']

Jay Hamilton Over a year ago

I am not sure, I thought that would return the array. Could you store it in a key value pair instead of the array when you build it? arr.push({[i]: data[i]}). then use the find().

khaos11 Over a year ago

I can try, and thought doing so, but couldn't figure out how. And how would that alter the find().

khaos11 Over a year ago

Just changing "arr.push([i, data [i]])" to "arr.push({[i]: data[i]})" didn't change the return. With obj[i]:data [i]; I get an error "Unexpected token :" I added a brace "}" at the end thinking that might be the issue but no change.

khaos11 Over a year ago

I finally got it thanks for all the help - it led me to figuring it out. I don't know if its the most elegant but it works. I'll post the solution under my question and answer it as well.

Collectives™ on Stack Overflow

Search node js array for partial match with variable, return index or value

3 Answers 3

Comments

3 Comments

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

3 Comments

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related