Babel preset for Expo that won't transpile all the way back to ES5
Using the default expo/metro preset for Babel will yield you code that's pretty portable,
but uses more transforms than are strictly necessary. Modern browsers support destructuring,
computed properties, ES6 classes, arrow functions, for-of, and a slew of other features that
are transpiled away by metro-react-native-babel-preset. Simply by not doing that, we can
emit better source maps and cleaner code for debugging.
These syntax elements will be transpiled away
- Expo vector icons transform
- Flow syntax
- Decorators
- Class properties
- Nullish coalescing
- Optional chaining
- Optional catch binding
- Dynamic import
- Export default from
- JSX
- JSX sourcemap
- TypeScript
- (optionally) Import/export => CommonJS
Use metro/expo preset if you use these syntax elements AND your target browser doesn't support them.
- Block scoping
- Computed properties
- Destructuring
- Integer literals
- Rest/default parameters
- Shorthand properties
- Sticky regex
- Unicode regex
- Arrow functions
- ES6 classes
- For-of
- Spread
- Template literals
- Exponentiation operator
- Object.assign
- Object rest/spread
- Symbol members