How to Add Auto Caching to Your JS Template Engine

In one of my articles I showed you how to create a simple JS template engine. In this article I will show you how to add simple caching to the compilation of our templates.

How Caching Works with JS Template Engines

Caching with our template engine is pretty simple. We just keep a key value object and use template strings as keys and functions as values. This will make subsequent uses of a template faster.

Implementing it inside Compile

All our compile function is this:

const compile = (template) => {
    return new Function("data", "return " + compileToString(template))
}

Let's rename this to

compileToFunction

const compileToFunction = (template) => {
    return new Function("data", "return " + compileToString(template))
}

Now let's create a cache. We will use a 

Map

const cache = new Map();

Now let's add a 

compile

cache

All we need to do is check if the 

cache.has(template)

const compile = (template) => {
    if (cache.has(template)) {
        return cache.get(template);
    } else {
        const compiledFunction = compileToFunction(template);
        cache.set(template, compiledFunction);
        return compiledFunction;
    }
}

Changing Our Render Function

Currently our 

render

var render = (template, data) => {
    return template.replace(/{{(.*?)}}/g, (match) => {
        return data[match.split(/{{|}}/).filter(Boolean)[0]]
    })
}

I think we should change it to use 

compile

compile

data

const render = (template, data) => {
    return compile(template)(data);
}

Conclusion

In this tutorial I showed how to extend the template engine we made in a previous post with caching for faster compilation and rendering.

Other Articles You Might Like

1. Creating a JS Template Engine
2. 14 JS Template Engines

Also published here.