@proteria/metadata v0.0.7

metadata

Babel plugin to emit decorator extensive metadata information, similar to TypeScript compiler, but supports lazy initialization, circular dependencies, generics and optional types.

Getting Started

In your .babelrc or other Babel configuration file, add the following:

{
  "plugins": [
    "@proteria/metadata/babel",
    ["@babel/plugin-proposal-decorators", { "legacy": true }],
    ["@babel/plugin-proposal-class-properties", { "loose": true }]
  ]
}

API

Documentation

Example

To generate field decorators automatically with typeorm:

import { Column } from "typeorm";
import { __decorate as decorate } from "tslib";
import { getClassProperties, getClassPropertyType } from "@proteria/metadata";

@annotate
class DataTable {
  name: string;
  id: number;
}

function annotate(Class: new (...args: any[]) => any) {
  for (const propertyName of getClassProperties(Class)) {
    const { typeFactory, nullable, value } = getClassPropertyType(
      Class,
      propertyName
    );
    decorate(
      [
        Column(typeFactory, {
          ...(nullable && { nullable }),
          ...(value && { default: value }),
        }),
      ],
      Class.prototype,
      propertyName
    );
  }
}

Working with libraries that use TypeScript metadata

You can decorate classes with emitDecoratorMetadata to enable interop with libraries that use TypeScript emitted metadata.

import { emitDecoratorMetadata } from "PENDING_PACKAGE_NAME";

@emitDecoratorMetadata
class Person {
  firstName: string;
  middleName?: string;
  lastName: string;

  getName() {
    return this.firstName + " " + this.lastName;
  }
}