TIL: Express Query Strings and Handlebar Arrays

I got a chance to work on my side project a little more at work today (though to be fair it’s hardly a side project as it’s going to be used to do actual work), and things are really starting to come together. One of the big things that I got working today involved handling query strings with express.

Express and Query Strings

Express makes handling query strings super easy. Lets suppose you have the following route configured in your app:

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app.get('/testing', (req, res) => {
    res.setHeader('Content-Type', 'application/json');
    res.send({ id: 1234 });
});

If you were to access the /testing route on the server, you’d get back the json payload with {"id": 1234}. Now, if you wanted to be able to support some type of query string on this route like /testing?bananas=3, you would be able to use res.query to get your query parameters in object form. The previous banana example would return the following:

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{"bananas": 3}

The same logic applies if you have more that one parameter. Say we expand out this example with /testing?bananas=3&apples=4&grapes=1. You’d see the following object in res.query:

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{"bananas": 3, "apples": 4, "grapes": 1}

Express Handlebars and Arrays

Something else I remembered that I learned today that took a bit of searching to find an answer/example for. When using express-handlebars and you’re passing in an array to your template, if you want to iterate over this array and use the value, you use the #each tag along with a this tag to actually use the value.

For instance, suppose that I have an array of four numbers: [12, 34, 45, 221]. Passing them into my html template, I would do the following to iterate through them:

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<div>
{% raw %}
    {{#each list}}
    <ul>{{this}}</ul>
    {{/each}}
{% endraw %}
<div>

That would give you an unordered list of the four numbers you passed in.

💚