babel-plugin-replace-named-exports

Babel plugin to replace named exports with configurable values. This might be useful for feature flags and tree shacking.

I copied most of the code from babel-plugin-debug-macros. It didn't fit my needs for matching local modules and it allows only boolean for the exports. Probably you want to use that module if it fits your needs.

Setup

The plugin can be configured to replace the exports for multiple files. To match the appropriate module you can use a string (for external modules) or a regex (for local modules).

{
  plugins: [
    [
      'babel-plugin-replace-named-exports',
      {
        modules: [
          {
            match: 'debug',
            exports: { DEBUG: true },
          },
          {
            match: /\/my-local-config$/,
            exports: {
              FEATURE_A: true,
              FEATURE_B: false,
              VERSION: 1.2,
              getLanguage: 'en',
            },
          },
        ],
      },
    ],
  ];
}

Examples

import { DEBUG } from 'debug';
import { FEATURE_A, FEATURE_B, VERSION, getLanguage } from './my-local-config';

if (DEBUG) {
  console.log('debug');
}

if (FEATURE_A) {
  console.log('FEATURE_A');
} else if (FEATURE_B) {
  console.log('FEATURE_B');
}

if (getLanguage() === 'en') {
  console.log('Language is en');
}

console.log(VERSION);

Transforms to:

if (true) {
  console.log('debug');
}

if (true) {
  console.log('FEATURE_A');
} else if (false) {
  console.log('FEATURE_B');
}

if (getLanguage() === 'en') {
  console.log('Language is en');
}

console.log(1.2);

If you set the export to null the export will not be removed.

{
  plugins: [
    [
      'babel-plugin-replace-named-exports',
      {
        modules: [
          {
            match: /\/my-feature-flags$/,
            exports: { FEATURE_A: true, VERSION: null },
          },
        ],
      },
    ],
  ];
}

import { FEATURE_A, VERSION } from './my-feature-flags';

if (FEATURE_A) {
  console.log('FEATURE_A');
}

console.log(VERSION);

Transforms to:

import { VERSION } from './my-feature-flags';

if (true) {
  console.log('FEATURE_A');
}

console.log(VERSION);

If an export used in the code is not configured in the plugin options, the plugin will throw an error.