// Read the browserslist configuration containing Angular's browser support policy.

const angularBrowserslist = (0, browserslist_1.default)(undefined, {

path: require.resolve('../../.browserslistrc'),

});

// Use Angular's configuration as the default.

browserslist_1.default.defaults = angularBrowserslist;

// Get the minimum set of browser versions supported by Angular.

const minimumBrowsers = new Set(angularBrowserslist);

// Get browsers from config or default.

const browsersFromConfigOrDefault = new Set((0, browserslist_1.default)(undefined, { path: projectRoot }));

// Get browsers that support ES6 modules.

const browsersThatSupportEs6 = new Set((0, browserslist_1.default)('supports es6-module'));

const nonEs6Browsers = [];

const unsupportedBrowsers = [];

for (const browser of browsersFromConfigOrDefault) {

if (!browsersThatSupportEs6.has(browser)) {

// Any browser which does not support ES6 is explicitly ignored, as Angular will not build successfully.

browsersFromConfigOrDefault.delete(browser);

nonEs6Browsers.push(browser);

}

else if (!minimumBrowsers.has(browser)) {

// Any other unsupported browser we will attempt to use, but provide no support for.

unsupportedBrowsers.push(browser);

}

}

if (nonEs6Browsers.length) {

logger.warn(`One or more browsers which are configured in the project's Browserslist configuration ` +

'will be ignored as ES5 output is not supported by the Angular CLI.\n' +

`Ignored browsers:\n${nonEs6Browsers.join(', ')}`);

}

if (unsupportedBrowsers.length) {

logger.warn(`One or more browsers which are configured in the project's Browserslist configuration ` +

"fall outside Angular's browser support for this version.\n" +

`Unsupported browsers:\n${unsupportedBrowsers.join(', ')}`);

}

return Array.from(browsersFromConfigOrDefault);