rollup.config.ts

/**
 * Rollup Config.
 */

import rollupPluginNodeResolve from '@rollup/plugin-node-resolve';
import rollupPluginTypescript from '@rollup/plugin-typescript';
import rollupPluginAutoExternal from 'rollup-plugin-auto-external';
import rollupPluginDts from 'rollup-plugin-dts';
import rollupPluginTerser from '@rollup/plugin-terser';
import rollupPluginGzip from 'rollup-plugin-gzip';

import pkg from './package.json' assert {type: 'json'};

const common = {
    input: 'src/index.ts',

    output: {
        sourcemap: false
    },

    external: [],

    treeshake: {
        annotations: true,
        moduleSideEffects: [],
        propertyReadSideEffects: false,
        unknownGlobalSideEffects: false
    }
};

/**
 * Get new instances of all the common plugins.
 */
function getPlugins(tsconfig = 'tsconfig.build.json') {
    return [
        rollupPluginAutoExternal(),
        rollupPluginNodeResolve(),
        rollupPluginTypescript({
            tsconfig
        })
    ];
}

const copyright = `/*!
 * ${pkg.name} v${pkg.version}
 * Copyright ${new Date().getFullYear()} ${pkg.author.name}
 * Released under the ${pkg.license} License
 * ${pkg.homepage}
 */
`;

/**
 * Get the intended boolean value from the given string.
 */
function getBoolean(value: unknown) {
    if (value === undefined) {
        return false;
    }
    const asNumber = Number(value);
    return Number.isNaN(asNumber)
        ? String(value).toLowerCase() === 'false'
            ? false
            : Boolean(String(value))
        : Boolean(asNumber);
}

const buildTypesOnly = getBoolean(process.env.BUILD_TYPES_ONLY);

/**
 * The common JS build.
 */
const cjs = {
    ...common,

    output: {
        ...common.output,
        file: pkg.main,
        format: 'cjs'
    },

    plugins: getPlugins()
};

/**
 * The esm build.
 */
const esm = {
    ...common,

    output: {
        ...common.output,
        file: pkg.module,
        format: 'esm'
    },

    plugins: getPlugins()
};

/**
 * The web script build.
 */
const web = {
    ...common,

    output: {
        ...common.output,
        sourcemap: true,
        file: 'dist/web/iter-ops.min.js',
        format: 'iife',
        name: 'iterOps',
        banner: copyright
    },

    plugins: [
        ...getPlugins('tsconfig.build.web.json'),
        rollupPluginTerser({
            format: {
                comments: 'some'
            }
        }),
        rollupPluginGzip()
    ]
};

/**
 * The web module build.
 */
const webModule = {
    ...web,

    output: {
        ...web.output,
        file: 'dist/web/iter-ops.min.mjs',
        format: 'esm'
    },

    plugins: [
        ...getPlugins('tsconfig.build.web.json'),
        rollupPluginTerser({
            format: {
                comments: 'some'
            }
        }),
        rollupPluginGzip()
    ]
};

/**
 * The types.
 */
const dts = {
    ...common,

    output: {
        file: pkg.types,
        format: 'esm'
    },

    plugins: [rollupPluginDts()]
};

export default buildTypesOnly ? dts : [cjs, esm, web, webModule, dts];