ts-named

Ts-Named : TypeScript Transformer for extracting variable name

Transforms :

import { named } from 'ts-named';
// ...
const SOME_ID = named(id => ({ ID: id, TYPE: 'Typed' }));

console.log(SOME_ID.ID);

To :

const SOME_ID = (id => ({ ID: id, TYPE: 'Typed' }))('SOME_ID');

console.log(SOME_ID.ID); // "SOME_ID"

Usage

ts-named declares a named function that receives an arrow function as parameter :

export declare function named<T>(idF: (id: string) => T): T;

The transformation expects it to be used before a variable declaration as follows :

import { named } from 'ts-named';
const SOME_ID = named(id => ({ ID: id, TYPE: 'Typed' }));

After the transformation the import and the function usages are removed. The named function usage is replaced with an immediately invoked arrow function (IIAF), with the variable name as argument.

Configuration

TypeScript compiler does not provide a standard way of including AST transformers to the tsc. You need to configure the build tool you use.

Webpack

const tsNamed = require('ts-named');

module.exports = {
  // ...etc...
  module: {
    rules: [
      {
        test: /\.tsx?$/,
        use: [
          {
            loader: 'ts-loader', // or awesome-typescript-loader
            options: {
              getCustomTransformers: () => ({ before: [tsNamed()] }),
            },
          },
        ],
      },
    ],
  },
};

Gulp

const gulp = require('gulp');
const ts = require('gulp-typescript');
const tsNamed = require('ts-named');

gulp.task('typescript', function() {
  gulp
    .src('src/**/*.ts')
    .pipe(
      ts({
        getCustomTransformers: () => ({ before: [tsNamed()] }),
      })
    )
    .pipe(gulp.dest('dist'));
});

Jest (with ts-jest)

In jest.config.js

    globals: {
        'ts-jest': {
            astTransformers: ['ts-named']
        }
    }

tsc (with ttypescript)

Alternatively you can use the ttypescript wrapper.

In tsconfig.json

{
  "compilerOptions": {
    "plugins": [{ "transform": "ts-named" }]
  }
}

Then configure different build tools to use the ttypescript instead of tsc, as shown here : https://github.com/cevek/ttypescript