esbuild

0.28.0 · active · verified Sat Apr 18

esbuild is an extremely fast JavaScript and CSS bundler and minifier. The current stable version is v0.28.0. The project maintains an active release schedule, frequently delivering patch updates and minor versions (e.g., v0.27.x, v0.28.x) within short periods, sometimes multiple per month, indicating rapid development and responsiveness to issues.

Common errors

```
SyntaxError: Class field initializers are not supported by the current target environment
```
cause TypeScript parameter properties were incorrectly lowered for target environments that don't support class fields in esbuild versions 0.27.0-0.27.6.

fix Upgrade esbuild to version `0.27.7` or newer.
```
[ERROR] Expected "and", "or", or end of input but found "{"
```
cause A regression in esbuild (v0.25.11 - v0.27.3) caused incorrect parsing of CSS media queries with `or` clauses, leading to invalid CSS.

fix Upgrade esbuild to version `0.27.4` or newer.
```
ReferenceError: [variable_name] is not defined
```
cause A bug in the bundler (prior to v0.27.1) incorrectly handled `var` declarations nested inside `if` statements when importing ES modules via `require`, leading to hoisting issues.

fix Upgrade esbuild to version `0.27.1` or newer.

Warnings

breaking esbuild v0.27.0 introduced deliberate backwards-incompatible changes. Users are strongly advised to pin exact versions or use patch-only version ranges to prevent unexpected upgrades.
Fix: Pin `esbuild` to an exact version (e.g., `"esbuild": "0.28.0"`) or use `~` for patch updates only (e.g., `"esbuild": "~0.28.0"`) in `package.json`.
gotcha Prior to v0.27.7, esbuild might incorrectly generate class fields for TypeScript parameter properties in target environments that don't support them, leading to runtime errors.
Fix: Upgrade to `esbuild@0.27.7` or later.
gotcha esbuild versions from 0.25.11 to 0.27.3 had a regression in CSS media query parsing, specifically failing to correctly wrap `or` clauses with parentheses, resulting in malformed CSS output.
Fix: Upgrade to `esbuild@0.27.4` or later.
gotcha esbuild v0.25.11 introduced a minification regression where duplicate CSS media rules were not correctly removed, especially for rules with `<media-type> and <media-condition-without-or>` grammar.
Fix: Upgrade to `esbuild@0.25.12` or later.

Install

npm install esbuild npm
yarn add esbuild yarn
pnpm add esbuild pnpm

Imports

build
```
import { build } from 'esbuild'
```

Quickstart

Bundles a TypeScript file `src/index.ts` into `dist/bundle.js` for a Node.js environment, targeting ES2022.

import { build } from 'esbuild';

const entryPoint = 'src/index.ts';
const outFile = 'dist/bundle.js';

await build({
  entryPoints: [entryPoint],
  bundle: true,
  outfile: outFile,
  platform: 'node',
  target: 'es2022'
}).then(() => {
  console.log(`Successfully bundled ${entryPoint} to ${outFile}`);
}).catch(() => {
  process.exit(1);
});

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