keepNames

• Type: boolean
• Optional

Defined in: options/output-options.ts:678

Keep name property of functions and classes after bundling.

When enabled, the bundler will preserve the original name property value of functions and classes in the output. This is useful for debugging and some frameworks that rely on it for registration and binding purposes.

Consider the following input files:

lib.js

export class Test {}
console.log(Test.name); // Expected: "Test"

export function test() {}
console.log(test.name); // Expected: "test"

main.js (entry)

import { Test as T, test as t } from './lib';

export class Test extends T {}

export function test() {}

Output with keepNames: false (default):

var Test$1 = class {};
console.log(Test$1.name); // "Test$1" - not the original name!
function test$1() {}
console.log(test$1.name); // "test$1" - not the original name!

var Test = class extends Test$1 {};
function test() {}

export { Test, test };

Output with keepNames: true:

// NOTE: `__name` is a helper function that sets `name` property

var Test$1 = class {
  static {
    __name(this, 'Test');
  }
};
console.log(Test$1.name); // "Test" - preserved!
function test$1() {}
__name(test$1, 'test');
console.log(test$1.name); // "test" - preserved!

var Test = class extends Test$1 {};
function test() {}

export { Test, test };

Default

false