https://github.com/clo4/deno_substitute

Simple & flexible variable substitution for Deno. Perfect for environment variables.
https://github.com/clo4/deno_substitute

deno environment-variables envsubst substitution

Last synced: 15 days ago
JSON representation

Simple & flexible variable substitution for Deno. Perfect for environment variables.

• Host: GitHub
• URL: https://github.com/clo4/deno_substitute
• Owner: clo4
• Created: 2021-03-21T11:44:26.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2021-03-22T08:47:23.000Z (over 3 years ago)
• Last Synced: 2024-10-26T06:51:53.603Z (20 days ago)
• Topics: deno, environment-variables, envsubst, substitution
• Language: TypeScript
• Homepage:
• Size: 10.7 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

        
# deno_substitute

**Simple, familiar, fast-enough variable substitution.**


Perfect for environment variables, flexible enough for whatever.




## Usage

`substitute` substitutes variables using a function.

```typescript

import { substitute } from "https://deno.land/x/[email protected]/mod.ts";

substitute("Welcome $HOME", Deno.env.get);

// => "Welcome /home/user"

substitute("Welcome $HOME", (s) => s.toLowerCase());

// => "Welcome home"

```

It's strict by default but designed to recover from errors gracefully.

```typescript

substitute("Hello, ${}", (x) => x);

// NoNameError: Expected variable name at column 8

substitute("Hello, ${}", (x) => x, { strict: false });

// => "Hello, ${}"

```

Bash and Windows CMD-style variables are both accepted, and can be disabled

individually.

```typescript

substitute("$HOME ${HOME}", (x) => x.toLowerCase());

// => "home home"

substitute("$HOME ${HOME}", (x) => x.toLowerCase(), { dollar: false });

// => "$HOME ${HOME}"

substitute("%USERPROFILE%", (x) => x.toLowerCase());

// => "userprofile"

substitute("%USERPROFILE%", (x) => x.toLowerCase(), { percent: false });

// => "%USERPROFILE%"

```

You can use a literal $ or % by doubling it, like `"$$"` or `"%%"`.




## Contributing

I'll endeavour to keep it working but I probably won't be adding anything new

myself. It does what I need it to. I'm more than happy to accept and help out

with PRs.

### Fair warning, though...

This code is extremely messy. The only goal when writing it was to make it work,

not to make it maintainable. Any negative side effects as a result of exposure

should be dealt with by a medical professional.