CODEWITHSUNDEEP
javascriptarraysnode.jscsv
Imran Chowdhry
Imran Chowdhry

Reputation: 59

newbie trying to return 2d array from fastcsv but returning undefined

I have this code here

function marketInfo() {
    var market_data = [];
    csv
    .fromPath("market_info.csv")
    .on("data", function(data) {
        if (data.length != 0) {
            market_data.push(data);
        }
    })
    .on("end", function() {
        for (var i=0; i < market_data.length; i++) {
            result.push(market_data[i]);
        }
        // console.log(market_data);
        return market_data;
    })
}

It prints the data and I know someone mentioned something about callbacks in another post, but I don't quite understand... The data has 0 headers so it's inline with [['market_cap', '123456789']] and so on. When returning the array, it's undefined. I tried to search but I can't figure out whats the issue here

Upvotes: 1

Views: 104

Answers (1)

tadman
tadman

Reputation: 211740

Your return market_data function just yells into the void. It does nothing meaningful. The marketInfo function itself makes use of asynchronous code with callbacks. Unless you supply a callback to that function you have no way of capturing that return value.

function marketInfo(cb) {
    var market_data = [];
    csv
    .fromPath("market_info.csv")
    .on("data", function(data) {
        if (data.length != 0) {
            market_data.push(data);
        }
    })
    .on("end", function() {
        for (var i=0; i < market_data.length; i++) {
            result.push(market_data[i]);
        }
        // console.log(market_data);
        cb(null, market_data);
    })
}

Where your callback needs to be passed in:

marketInfo(function(err, market_data) {
  // Do stuff with data
});

As writing callback-driven code can be harrowing you might try and steer towards solutions based around either Promises or async/await instead.

Upvotes: 1

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