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Functions for Creating Types

A function wrapper allows you to utilize closures when creating custom types, opening up a wide range of possibilities.

Usage Examples

Adding a Tag

import { customType } from "encodexx"

export function strWithTag(tag: string) {
  return customType<string>({
    encode(buffer, str) {
      buffer.writeString(tag + str);
    },
    decode(buffer) {
      return buffer.readString();
    },
    guard(data) {
      return typeof data === "string";
    },
    name: "stringWithTag " + tag,
  });
}

import { Serializer } from "encodexx"

import { strWithTag } from "./str-with-tag.ts"

const serializer = new Serializer({
  name: strWithTag("Dr. ")
})

const encoded = serializer.encode({
  name: "House"
})

console.log(serializer.decode(encoded)) // {name: "Dr. House"}

Caution

For proper schema comparison in the .equal() method, you must use a unique name for each distinct type. In this example, we append the tag to the type name.

Using type or t.none

import { customType, TConvertValueToType } from "encodexx"

export function orNone<T extends TSchema>(type: T) {
  if (TYPE_SYMBOL in type) return t.or(t.none, type);
  return t.or(t.none, t.schema(type));
}

What’s Next?

For a more advanced example of using functions to create types, check out the examples.