Reusable Template Literals: Exposing the Hidden Potential

While template literals in ES6 are extensively utilized, the perception persists that they are eternally bound to the moment of their creation, lacking the flexibility to be reused and dynamically updated. This article challenges that notion, exploring the possibility of transforming template literals into reusable and dynamic documents.

The essence of a traditional template lies in the ability to inject tokens at runtime, evaluable whenever necessary. However, ES6 template literals appear to evaluate their substitutions at declaration time, limiting their practicality.

The Essential Catalyst: The Function Constructor

To overcome this apparent limitation, we employ the Function constructor as an intermediary. By utilizing this construct, we can defer the interpolation process until the function is invoked:

const templateString = "Hello ${this.name}!";
const templateVars = {
  name: "world",
};

const fillTemplate = function (templateString, templateVars) {
  return new Function(
    "return `"   templateString   "`;"
  ).call(templateVars);
};

console.log(fillTemplate(templateString, templateVars));

In this example, the fillTemplate function accepts the template string and a set of variables to be interpolated. Within the function, we construct a function that, when executed, returns the template string with the values from templateVars injected at runtime.

Benefits of Reusable Template Literals

The resulting reusable template literals offer numerous advantages:

• Dynamic interpolation: Values can be interpolated into the template at runtime, providing greater flexibility.
• External interpolation: Templates can be sourced from external files, allowing for easy maintenance and collaboration.
• Extended capabilities: Additional features like template tags can be integrated with some ingenuity.

While this solution introduces certain limitations, such as the inability for inline JavaScript logic, workarounds can be developed.

Conclusion

By employing the Function constructor, we unlock the true potential of ES6 template literals. We transform them from static strings to reusable, dynamic templates, opening up new possibilities for code organization and flexibility. While the journey to fully recreate the functionality of traditional template engines continues, this technique provides a robust foundation for extending the capabilities of template literals.