@nx/webpack/src/plugins/nx-webpack-plugin/lib/get-terser-ecma-version.js

The Nx Plugin for Webpack contains executors and generators that support building applications using Webpack.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.getTerserEcmaVersion = getTerserEcmaVersion;
const path = require("path");
const fs = require("fs");
const browserslist = require("browserslist");
const VALID_BROWSERSLIST_FILES = ['.browserslistrc', 'browserslist'];
const ES5_BROWSERS = [
    'ie 10',
    'ie 11',
    'safari 11',
    'safari 11.1',
    'safari 12',
    'safari 12.1',
    'safari 13',
    'ios_saf 13.0',
    'ios_saf 13.3',
];
function getTerserEcmaVersion(projectRoot) {
    let pathToBrowserslistFile = '';
    for (const browserslistFile of VALID_BROWSERSLIST_FILES) {
        const fullPathToFile = path.join(projectRoot, browserslistFile);
        if (fs.existsSync(fullPathToFile)) {
            pathToBrowserslistFile = fullPathToFile;
            break;
        }
    }
    if (!pathToBrowserslistFile) {
        return 2020;
    }
    const env = browserslist.loadConfig({ path: pathToBrowserslistFile });
    const browsers = browserslist(env);
    return browsers.some((b) => ES5_BROWSERS.includes(b)) ? 5 : 2020;
}