I need help with ticker price action in JS

JavaScript
1

Hey everyone, I am following a youtube video that tracks the ticker price action using Python Flash as the back-end, and utilizes JS, HTML, CSS, JQUERY on the front-end however i am receiving an ample amount of errors for JS. I triple checked to make sure i copied exactly how he has written it. The video is 8 months old so I am not sure if this is outdated.

var tickers = JSON.parse(localStorage.getItem( key:'tickers')) || [];
var lastPrices: {} = {};
var counter : number = 15;

function startUpdateCycle() :void {
    updatePrices();
    var countdown : number = setInterval(handler:function () : void {
        counter--;
        $('#counter').text(counter);
        if (counter <= 0) {
            updatePrices();
            counter = 15;
        }

    }, timeout: 1000) 

}

$(document).ready(function () :void {
    
    tickers.forEach(function(ticker: T) :void {
        addTickerToGrid(ticker);
    });
   
    updatePrices();

    $('#add-ticker-form').submit(function(e) :void {
        e.preventDefault();
        var newTicker = $('#new-ticker').val().toUpperCase();
        if (!tickers.includes(newTicker)) {
            tickers.push(newTicker);
            localStorage.setItem('tickers', JSON.stringify(tickers))
            addTickerToGrid(newTicker);
                }
                $('new-ticker').val(' ');
                updatePrices();
    });

    $('#tickers-grid').on('click', '.remove-btn', funtion() : void {
        var tickerToRemove = $(this).data('ticker');
        tickers = ticker.filter(t => t !== tickerToRemove);
        localStorage.setItem('tickers', JSON.stringify(tickers))
        $('#${tickerToRemove}').remove();
    });

    startUpdateCycle();
});

function addTickerToGrid(ticker) :void {
    $('#tickers-grid').append('<div id="${ticker}" class="stock-box"><h2>${ticker}</h2><p id="${ticker}-price"</p><p id="${ticker}-pct"</p><button class="remove-btn" data-ticker="${ticker}">Remove</button></div>') 
}

function updatePrices() :void {
    tickers.forEach(function (ticker) :void {
        $.ajax({
            url: '/get_stock_data',
            type: 'POST',
            data: JSON.stringify(value: {'ticker': ticker}),
            contentType: 'application/json; charset=utf-8',
            dataType: 'json'
            success: funtion (data) :void {
                var changePercent : number = ((data.currentPrice - data.openPrice) / data.openPrice) * 100;
                var colorClass;
                if (changePercent <= -2){
                    colorClass = 'dark-red'
                } else if (changePercent < 0) {
                    colorClass = 'red'
                } else if (changePercent == 0){
                    colorClass = 'gray'
                }  else if (changePercent <= 2){
                    colorClass = 'green'
                } else{
                    colorClass = 'dark-green'
                }

                $('#${ticker}-price').text('$${data.currentPrice.toFixed(2)}');
                $('#${ticker}-pct').text('${changePercent.toFixed(2)}%');
                $('#${ticker}-price').removeClass('dark-red red grey green dark-green').addClass(colorClass);
                $('#${ticker}-pct').removeClass('dark-red red grey green dark-green').addClass(colorClass);

                var flashClass;
                if (lastPrices[ticker] > data.currentPrice) {
                    flashClass = 'red-flash';
                } else if (lastPrices[ticker] < data.currentPrice) {
                    flashClass = 'green-flash';
                } else {
                    flashClass = 'gray-flash';
                }
                lastPrices[ticker] = data.currentPrice;

                $('#${ticker}').addClass(flashClass);
                setTimeout(handler: funtion() :void {
                    $('#${ticker}').removeClass(flashClass);

                }, 1000);
            }
        });
    });
}

    tickers.forEach(function(ticker: T) : void {
        addTickerToGrid();
    });
   
})
2

I’ve edited your code for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.

You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.

Pre-formatted-text
Pre-formatted-text1356×380 401 KB

See this post to find the backtick on your keyboard.
Note: Backticks (`) are not single quotes (').

3

what errors are you getting?

4

The types aren’t actually in the code. They are type hints added by the IDE. He might be using Webstorm but I’m not sure (docs).

I would start by removing all the types. If you don’t know what types are, look at when he enters the code, the hints are added automatically and are not typed out. They are also dimmed or boxed differently than the actual code.