Text Modules

In a similar fashion to the json modules proposal text modules would be able to load text files as dependencies for a module. It requires using assert { type: "text" } to be treated as a text import with the default export being a string containing the file contents.

One important difference to consider other than just parsing it as a string would be the ability to specify an encoding if it's not provided in the response already. Specifics would be up to the implenting host, such as potentially defaulting to utf-8 or trying to infer it based on the contents.

Consider the following example:

import renderer from "renderer";
import template from "https://example.com/remote/template" assert { type: "text", encoding: "utf-8"  };

renderer.render(template, { a: 1, b:"foo"  });

Uses would include importing templates or files written in a DSL. (or just importing text of course)

4 Likes

Note: Node and WHATWG each have multiple different encodings they can load things as, ranging from the common UTF-8 and UTF-16LE to Node's transparently transcoded hexadecimal, Base64, and Latin-1 "encodings", and also it could be valuable to load a file not as a string, but as an array buffer (think: large pre-compiled tables). And of course, there's BOMs to worry about with Unicode in general.

I like the idea, but this...isn't as simple to spec out as it sounds. And to be quite honest, I would want much more quickly a portable way to transcode array buffers than this, because most platforms that have this kind of mechanism also offer a way to fetch those files asynchronously and get them in full as an array buffer, but transcoding...is admittedly a bit painful on most platforms. (WHATWG doesn't have actual transcoders, only encoders and decoders, and Node, while it has transcoders, lacks any sort of streaming support, so neither can really replace the other.)

2 Likes

Specifying an encoding might not even be necessary (you never do it when loading JavaScript or JSON files, which are also text files)

If you're in a browser environment, the encoding is normally provided via the Content-Type header. It's up to the server to be aware of the encoding, not the module that wishes to load the file.

In other enviornments, such as the server, or with a bundler, I guess there's currently isn't a way to let the JavaScript engine know the encoding of the file you're attempting to import, at least, I can't think of any way of doing so. So, perhaps it would be useful for this scenario.

Interesting, I never realized ES itself didn't have any stream encoding and transcoding capabilities built in. My proposal doesn't state any requirements as to what encodings must be supported by the host and I think except for a minimum requirement of utf-8 as the defacto standard it really shouldn't specify it and leave it up to implementation.
But transcoding capabilities might be worth exploring in their own idea. I think it's a task that is common enough to include it into ES. With node it's possible to work around their implementations shortcomings using native modules but in other environments it's not that simple after all.

Exactly. When the encoding is contained within the response it's trivial. But if the response header doesn't specify an encoding it's not so easy. One other advantage JSON has over text is that because the encoding can be more easily inferred based on the characters used if the implementation doesn't already require a uniform encoding for js and json files.
Text on the other hand can be anything. And yes, being able to specify an encoding was aimed more towards importing local files in a server/bundler context, for example web servers importing css files or html templates, or system utilities handling system files which were maybe standardized decades ago and were thus still using ascii/ansi type files.