JS with Types Start

jsconfig.json option

lib

  • Default the target's libraries, plus dom
  • Since TypeScript 2.0

lib lists TypeScript's own declaration files for built-in APIs: the ECMAScript standard library by year (es2022, es2024, esnext), the browser DOM (dom, dom.iterable), and a few more such as webworker. Without lib, TypeScript picks the files for your target and adds dom. With lib set, you get exactly the list.

The list is a statement about where your code runs. A browser project wants dom; a server or edge project wants it gone, so document is an error instead of a crash. One surprise: console is declared by the DOM library (and by @types/node), not by ECMAScript, so lib: ["es2022"] with no other types makes console.log an error too (TS2584).

At a glance

Write Leave it out for browser code. For code with no DOM (Node.js, Bun, Cloudflare), list the ES year alone: ["es2024"]
On the command line --lib
Type string[]
Default in TypeScript 5.9 the target's libraries, plus dom
TypeScript's description Specify a set of bundled library declaration files that describe the target runtime environment.
In the quick-start setups

The description is quoted from TypeScript's own option list (Apache-2.0); see the notices. The setup values are the checked configs on the quick-start pages.

Examples

main.js Error confirmed 5.9.3 TypeScript 5.9.3, run 21 October 2026: main.js(2,16): error TS2584: Cannot find name 'document'. Do you need to change your target library? Try changing the 'lib' compiler option to include 'dom'. main.js(5,3): error TS2584: Cannot find name 'console'. Do you need to change your target library? Try changing the 'lib' compiler option to include 'dom'. 6.0.3 TypeScript 6.0.3, run 21 October 2026: the same as 5.9.3. main.js(2,16): error TS2584: Cannot find name 'document'. Do you need to change your target library? Try changing the 'lib' compiler option to include 'dom'. main.js(5,3): error TS2584: Cannot find name 'console'. Do you need to change your target library? Try changing the 'lib' compiler option to include 'dom'. 7.0.2 TypeScript 7.0.2, run 21 October 2026: the same as 5.9.3. main.js(2,16): error TS2584: Cannot find name 'document'. Do you need to change your target library? Try changing the 'lib' compiler option to include 'dom'. main.js(5,3): error TS2584: Cannot find name 'console'. Do you need to change your target library? Try changing the 'lib' compiler option to include 'dom'. checked 21 October 2026 
const button = document.querySelector("button");error TS2584: Cannot find name 'document'. Do you need to change your target library? Try changing the 'lib' compiler option to include 'dom'.
button?.addEventListener("click", () => {
  console.log("clicked");error TS2584: Cannot find name 'console'. Do you need to change your target library? Try changing the 'lib' compiler option to include 'dom'.
});
lib without "dom": no document, and no console either.
jsconfig.json for this example 
{
  "compilerOptions": {
    "checkJs": true,
    "noEmit": true,
    "strict": true,
    "target": "es2022",
    "module": "nodenext",
    "types": [],
    "lib": [
      "es2022"
    ]
  },
  "include": [
    "*.js"
  ]
}
main.js TypeScript 5.9.3 TypeScript 5.9.3, run 21 October 2026: No errors. 6.0.3 TypeScript 6.0.3, run 21 October 2026: the same as 5.9.3. No errors. 7.0.2 TypeScript 7.0.2, run 21 October 2026: the same as 5.9.3. No errors. checked 21 October 2026 
const button = document.querySelector("button");
button?.addEventListener("click", () => {
  console.log("clicked");
});
lib with "dom": the browser globals are there.
jsconfig.json for this example 
{
  "compilerOptions": {
    "checkJs": true,
    "noEmit": true,
    "strict": true,
    "target": "es2022",
    "module": "nodenext",
    "types": [],
    "lib": [
      "es2022",
      "dom"
    ]
  },
  "include": [
    "*.js"
  ]
}

Lists that fit the usual projects

Starting points that match the checked setups in the quick start:

  • browser, no bundler: ["es2022", "dom", "dom.iterable"] (dom.iterable lets you loop over a NodeList with for…of)
  • Node.js: ["es2024"], with "types": ["node"] for process, console and the built-in modules
  • Cloudflare: ["es2024"] with the platform types in types (see the quick start)
  • Bun: ["esnext"] with "types": ["bun"], which is what Bun's documentation recommends

Gotchas

  • Setting lib replaces the default list; it does not add to it. "lib": ["dom"] alone loses the ECMAScript library.
  • A type package can bring globals of its own regardless of lib: @types/node declares console, setTimeout and more.

  • jsconfig.json option

    target

    target names the JavaScript version your runtime has. With noEmit it picks which built-in APIs exist: Promise.withResolvers needs es2024.

  • jsconfig.json option

    types and typeRoots

    types lists the @types packages whose globals the checker loads, like node for process. Without it, TypeScript 5.9 loads every @types package; 6.0 loads none.

  • Quick start

    Browser, no bundler

    Type-check JavaScript that the browser loads as module scripts: the DOM in lib, no Node.js types, and imports held to the exact paths a browser needs.

  • TypeScript error

    TS2583: Map, Set or Promise is missing because the target is old

    TS2583 and TS2585 mean Map, Set, Promise or Symbol are missing because the config targets ES5, the 5.9 default when no target is set. Set target.

  • TypeScript error

    TS2584: console is missing because lib leaves out the DOM

    TS2584 means console or document is unknown: lib lists only ECMAScript libraries and no Node.js types are loaded. Add @types/node or the dom library.

  • TypeScript error

    TS2550: A method newer than the configured library

    TS2550 means a built-in method such as .at() or replaceAll() is newer than the target or lib the config names. Raise target if your runtimes support the method.

Sources

Last reviewed 20 October 2026.