In Deno, when you first run a program, Deno downloads all related dependencies. These dependencies are cached for subsequent use and are not re-downloaded unless explicitly specified. To ensure using the latest version of dependencies, you can take the following approaches:
1. Using the --reload Flag
For instance, you can use the --reload flag when running a program to force Deno to re-download all dependencies, regardless of whether they have been cached. This ensures all dependencies are up-to-date. For example:
deno run --reload your_script.ts
If you only want to reload specific dependencies, you can specify their URLs, such as:
deno run --reload=https://deno.land/std@0.75.0/fs/mod.ts your_script.ts
2. Clearing Deno's Cache
Another approach is to completely clear Deno's cache. You can achieve this by running the following command:
deno cache --reload your_script.ts
This will clear all cached dependencies and re-download them.
3. Specifying the Latest Version of Dependencies
In your code, when importing modules, you can specify the exact version or use the latest version. For example, if you're using the standard library from deno.land, you can specify the version as follows:
import { serve } from "https://deno.land/std@0.90.0/http/server.ts";
Alternatively, to ensure you always use the latest version, you can omit the version number:
import { serve } from "https://deno.land/std/http/server.ts";
Note: Omitting the version number and always using the latest version may cause your code to suddenly stop working at some future point because newer versions might not be backward compatible.
Conclusion
Using the --reload flag is a simple and direct method to ensure your dependencies are always up-to-date. However, to avoid your code breaking in the future due to changes in dependencies, it's better to specify a stable version number, allowing you to control updates while maintaining dependency stability.