esbuild-plugin-modify-entrypoints/dist/mjs/plugin.js

esbuild plugin to modify entrypoint contents

import { readFile } from 'node:fs/promises';
export const PLUGIN_NAME = 'modify-entrypoints';
export const modifyEntrypointsPlugin = (...modifyFunctions) => ({
    name: PLUGIN_NAME,
    async setup(build) {
        const functions = modifyFunctions.flat();
        build.onResolve({ filter: /.*/ }, ({ path, resolveDir, kind }) => {
            if (kind === 'entry-point') {
                return {
                    path,
                    namespace: PLUGIN_NAME,
                    pluginData: {
                        resolveDir,
                    },
                };
            }
        });
        build.onLoad({ filter: /.*/, namespace: PLUGIN_NAME }, async ({ path, pluginData }) => {
            const contents = await readFile(path, 'utf8');
            return functions.reduce((results, fn) => {
                const innerResults = fn({
                    contents: results.contents,
                    loader: results.loader,
                    path,
                    resolveDir: pluginData?.resolveDir,
                    options: build.initialOptions,
                });
                const loader = innerResults.loader ?? results.loader;
                return {
                    ...results,
                    ...innerResults,
                    ...(loader ? { loader } : {}),
                    resolveDir: pluginData?.resolveDir,
                };
            }, {
                contents,
            });
        });
    },
});