optimise efficiency in display mysql query results in node.js

Question

I have a query that returns an entire table. The only way I found to display the data as an HTML table is by creating an array for each column:

var date = [];
for (var i in arr) {
    date[i] = arr[i].nullinfoDate;
}
var number = [];
for (var i in arr) {
    number[i] = arr[i].nullinfoNumber;
}
var bool = [];
for (var i in arr) {
    bool[i] = arr[i].nullinfoBool;
}
var text1 = [];
for (var i in arr) {
    text1[i] = arr[i].nullinfoText1;
}
var text2 = [];
for (var i in arr) {
    text2[i] = arr[i].nullinfoText2;
}

and then sending all the columns to the HTML template:

app.get('/', function (req, res) {
    res.render('index', {
        title: 'home',
        date: date,
        number: number,
        bool: bool,
        text1: text1,
        text2: text2
    });
});

But that feels extremely inefficient. Is there a better way to do that?

HTML (EJS) template:

<!DOCTYPE HTML>
<html>
<head>
    <meta charset="utf-8">
    <title><%= title %></title>
</head>
<body>
    <h1><%= title %></h1>
    <table>

    <% for(var i = 0; i < date.length; i++) {%>
    <tr>
        <td><%= date[i] %></td>
        <td><%= number[i] %></td>
        <td><%= bool[i] %></td>
        <td><%= text1[i] %></td>
        <td><%= text2[i] %></td>
    </tr>
    <% } %>

    </table>
</body>
</html>

Thanks! Could you also describe how exactly the data returned by your query (arr) look like? — Alex M
– Alex M, Commented Aug 19, 2016 at 7:51
[ RowDataPacket { NULLINFOId: 7, nullinfoDate: Wed Aug 17 2016 13:48:18 GMT+0300 (IDT), nullinfoNumber: 877, nullinfoBool: 0, nullinfoText1: 'word', nullinfoText2: 'phrase' }, RowDataPacket { NULLINFOId: 8, nullinfoDate: Wed Aug 17 2016 13:48:53 GMT+0300 (IDT), nullinfoNumber: 924, nullinfoBool: 1, nullinfoText1: 'something', nullinfoText2: 'stuff' }, etc... — user3187759
– user3187759, Commented Aug 19, 2016 at 7:58

Alex M · Accepted Answer · 2016-08-19 08:00:54Z

1

It seems it's enough to pass the data returned by your query directly:

app.get('/', function (req, res) {
    res.render('index', {
        title: 'home',
        data: arr
    });
});

Then in your template, you can just do:

<table>

<% for (let datum of data) {%>
<tr>
    <td><%= datum.nullinfoDate %></td>
    <td><%= datum.nullinfoNumber %></td>
    <td><%= datum.nullinfoBool %></td>
    <td><%= datum.nullinfoText1 %></td>
    <td><%= datum.nullinfoText2 %></td>
</tr>
<% } %>

</table>

answered Aug 19, 2016 at 8:00

Alex M

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2 Comments

user3187759 Over a year ago

It worked! Thanks. Only with var or const instead of let, but no matter

Alex M Over a year ago

@user3187759 Cool :)

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