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Pushing data to the browser

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Sometimes code on the server side needs to pass data to JavaScript code in the browser.

People solve it all sorts of ways, but Apostrophe provides really convenient solutions.

Passing data with the "json" filter in nunjucks

It is possible to send data from a Nunjucks template directly into a script tag without the risk of broken markup. For simple cases this is often the best way. Just use the json filter:

<script type="text/javascript">
var myData = {{ data | json }};

This will correctly stuff your data into myData, no matter how complex it is, as long as it is JSON-friendly (just about anything except functions, Date objects and regular expressions).

The JSON filter is smart enough to escape characters that are technically valid in JSON but would break your script tag.

Pushing data for every request

Sometimes data is important enough that you want the browser to see it on every single page request. For that, use apos.pushGlobalData.

When I do this on the server side:

  shoeBrands: [ 'nike', 'adidas' ]

I can see that data on the browser side:


Always pass an object to pushGlobalData. That object will be merged with the object on the browser side.

You can make as many calls as you need to. You may pass objects with properties that are objects, and so on. If it's compatible with JSON, it will work.

pushGlobalData will always escape your data correctly, so you don't have to worry about a double-quote in your data breaking a quoted string in your inline JavaScript, etc.

Pushing data for one request

Other times, data is only relevant to the current request. For that, use req.pushData:

  myShoeSize: 5

This works just like pushGlobalData, merging into the object in the browser:


The only difference is that the data is only pushed for the current request.

A warning

The pushGlobalData and pushData techniques work out of the box when you're preparing to render an entire page. If you're writing a page loader function, overriding index or show in a snippet subclass, or doing something similar, then they will work great for you. They also work great with the renderPage method provided by mixinModuleAssets, which is available in most modules.

If you are returning an HTML fragment as an AJAX response, you'll want to call apos.getGlobalData() and apos.getData(req) to obtain JavaScript source code ready to insert in your own script tag to do the work. or, just use the json filter.

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