const browserslist = require('browserslist'); const esbuild = require('esbuild'); const ESBUILD_SUPPORTED_TARGETS = new Set([ 'chrome', 'edge', 'firefox', 'hermes', 'ie', 'ios', 'node', 'opera', 'rhino', 'safari', ]); const parseBrowserslist = (browserslistResult) => { return browserslistResult.map((browsers) => { const [family, version] = browsers.split(' '); let normalizedVersion = version; // browserslist can return a range: safari15.2-15.4 if (version.indexOf('-') >= -1) { // we take the lowest version [normalizedVersion] = version.split('-'); } return { family, version: normalizedVersion, }; }); }; const mapBrowserslistToESBuildTarget = (browsersList) => { return parseBrowserslist(browsersList) .filter(({ family, version }) => { if (!ESBUILD_SUPPORTED_TARGETS.has(family)) { console.warning('Unknown ESBuild target %s, version %s', family, version); return false; } return true; }) .map(({ family, version }) => { return `${family}${version}`; }); }; module.exports = { target: mapBrowserslistToESBuildTarget(browserslist()), supported: { 'optional-chain': false, 'nullish-coalescing': false, 'class-static-field': false, 'class-field': false, }, implementation: esbuild, };