Template engines like EJS and Handlebars are good. But sometimes, you don't want all the code and the complexity that comes with them. You only want a simple variables injection with components support. Well, that is what Sprightly is for, it is a one-filer that lets you use those tiny features without having to include or think about anything else.

Guide and APIs

When you import * as APIs from "sprightly" you get access to the following APIs:

• sprightly.

  The template engine function. Interface:

  function sprightly(entryPoint: string, data: Data, options?: Options): string

  Given an entryPoint, the function will return the file injected with the variables referenced in data. The function also receives an options argument containing an object of options to modify the function’s behavior. Example:

  <!-- ./nested/file.html -->
  
  {{ name }} says {{> ../message.html }}.

  <!-- ./message.html -->
  
  Hi

  Notes:

  • {{ var }} is the syntax for referencing a variable.
  • {{> ./path/to/file }} is the syntax for referencing a component.

  sprightly("./nested/file.html", { cool: "Osid" })
  // => "Osid says Hi".

• sprightlyAsync.

  A promisifed version of the sprightly function described above.

• Data.

  The interface for the data parameter defind in sprightly's function.

  interface Data {
    [key: string]: string | number | Array<string | number | Data> | Data
  }

  The key is the name of the variable referenced in the template. It can hold a string, a number, a recuresive Data object, or an array of all of the mentioned types. This means that the template can use subscripting syntax to reference deeply nested variables. Example:

  const data = {
    property: {
      nested: [{ anotherProperty: ["foo", "bar"] }],
    },
  }
  
  sprightly("./file.html", data)
  // => "bar"

  In template:

  <!-- ./file.html -->
  
  {{ property.nested.0.anotherProperty.1 }}
  

  The solution used for the subscribting logic is get-value. Its syntax is simple, but you can visit its page if you want to inspect it more thouroughly.

• Options.

  The interface for the options parameter defind in sprightly's function.

  interface Options {
    keyFallback?: string
    throwOnKeyNotfound?: boolean
    cache?: boolean
  }

  Option	Default	Description
  throwOnKeyNotFound	false	Determines whether to throw an error if a referenced variable isn’t found.
  keyFallback	empty string	Contains the value to be used if a referenced variable doesn’t exist. Doesn’t matter if throwOnKeyNotFound is set to true.
  cache	If available, it is set to the cache value sent through Express’s options that comes from app.set("view cache", truthValue), if not, it is set to false.	Determines whether to cache processed entry points or not. Typically you would want to set this to true in production and false in development.

• SprightlyError.

  The error class thrown by the sprightly function. Occusions that the error is thrown at:

  • If the passed entryPoint argument isn’t a string.
  • If the passed data argument isn’t an object.
  • If the passed options argument isn’t an object.
  • If the passed entryPoint doesn’t exist.
  • If a referenced variable isn’t found. Triggered only if throwOnKeyNotFound is set to true.
  • If a referenced component isn’t found.

Usage with ExpressJS

// to import the Express adapter
import sprightlyExpress from "sprightly/express"

/* This sets up the template engine.
 * Express by default requires and calls the necessary template engine according to
 * the extension of the file to render (e.g. .hbs). But because sprightly has no specific
 * file extension to allow it to be used with any file, you have to set this up manually.
 */
app.engine(
  "html",
  sprightlyExpress({
    cache: false,
    keyFallback: "obada",
    throwOnKeyNotfound: false,
  }),
)

app.get("/", (_, res) => {
  res.render("./nested/file.html", { cool: "sprightly" })
})