0.1.3 • Published 6 years ago
optionally v0.1.3
optionally 
Option parser with schema definition and descriptive errors:
const schema = {
port: { default: 3000, type: Number },
public: { default: "public", type: [String, Boolean] }
};
// All of these result in `{ port: 3000, public: "public" }`
optionally(schema); // Uses the defaults
optionally(schema, { port: "3000" }); // Cast to a number since it's possible
optionally(schema, {}, process.env); // `.env` is `PORT=3000`
// Clear error messages:
optionally(schema, { port: "cow" });
// TypeError: The option `port` should be a number like `{ port: 3000 }` instead of the string "cow".The arguments for each of the options, with all of them being optional:
| key | description | type |
|---|---|---|
find() | manually get the value from the params | function |
↳ env | name of the environment variable to use | string |
↳ arg | name of the argument to use | string |
↳ inherit | for subtrees, get the value from parent | boolean, string |
↳ default | value to use if none is provided | any |
parse() | parse the previously found value | function |
↳ extend | extend the default object with the value | boolean |
validate() | manually check that the value is correct | function |
↳ type | type must match (or cast) to one of these | function, string, array |
↳ required | value must be provided and found | boolean |
↳ enum | it has to match exactly one of these | array |
options | define the schema of the children | object |
Internally it works in three steps, if you provide the main function then it will not perform the other actions:
find(): usesenv>arg>inherit>default(in order) to attempt to get a value out of the arguments and environment.clean(): usesextend,fileandfolderto expand the previously found value.validate(): usestype,required,enum,
Helpers:
__root: "abcdef": if a single option is provided that is not an object, it will be converted into{ abcdef: options }. Example: accept a port as a single argument{ __root: "port" }+server(3000)=server({ port: 3000 }).__mode: "strict": defines what to do with options that are not defined."strict"will throw with keys that are not in the schema,"remove"will delete these extra keys and"flexible"will pass through any extra arguments.