update readme

package.json

@@ -4,7 +4,15 @@
  "publishConfig": {
  "access": "public"
  },
- "keywords": [],
+ "keywords": [
+ "cli",
+ "node",
+ "parse",
+ "argument",
+ "config",
+ "utility",
+ "typescript"
+ ],
  "homepage": "https://github.com/eegli/tinyparse",
  "author": {
  "name": "Eric Egli",

readme.md

@@ -1 +1,45 @@
 # Tinyparse
+
+### Highly opiniated, type-safe parsing module for object literals and Node's `process.argv`.
+
+I use this mostly for other pet projects of mine, but why not make it public.
+
+- TypeScript first
+- Promise-based
+- Fast, zero dependencies
+- Supports object literals and arrays of strings
+
+The whole thing is quite opinionated and assumes some things. It exports a single parser factory function that accepts either an object literal or array of strings (usually, `process.argv.slice(2)`)
+
+Whatever config is parsed with the `parser` function created by the factory will get the key-value pairs from the default config, but with updated keys if they are valid.
+
+```ts
+import { parserFactory } from '@eegli/tinyparse';
+
+const defaultInput = {
+ name: '',
+ age: 0,
+ hasDog: true,
+};
+
+const userInput = {
+ name: 'eric',
+ age: 12,
+ what: 'is he doing',
+};
+
+const parse = parserFactory(defaultInput);
+const parsedInput = await parse(userInput);
+
+/* -- parsedInput 
+{
+ name: 'eric',
+ age: 12,
+ hasDog: true
+}
+*/
+```
+
+1. The object literal argument can only have strings, numbers and booleans as object keys
+2. It expects an object that specifies the **exact types** that are desired for the parsed arguments. The exact values of `defaultInput` don't matter as long as the types are correct.
+3. Invalid keys are ignored, invalid value types are rejected