JS with Types Start

jsconfig.json option

target

  • Default es5
  • Tested with TypeScript 5.9

target names an ECMAScript version. When tsc writes output, it rewrites newer syntax down to that version. With noEmit nothing is rewritten, so in a JavaScript project target does one job: unless you set lib, it picks the built-in declarations, and so decides which methods exist. Promise.withResolvers and Object.groupBy are ES2024; with target: "es2022" they are TS2550.

Pick the newest year that every runtime you support implements in full. In TypeScript 5.9 a config without target gets es5, unless module is nodenext (which implies esnext) or node20 (es2023). TypeScript 6.0 changes the default to the newest year and deprecates es5.

At a glance

Write The ECMAScript year your oldest supported runtime fully implements, for example "es2022" or "es2024"
On the command line --target
Type string
Default in TypeScript 5.9 es5 (module nodenext implies esnext, and node20 implies es2023)
Default from TypeScript 6.0 the newest ECMAScript year (es2025 in 6.0); es5 is deprecated (TypeScript 6.0)
TypeScript's description Set the JavaScript language version for emitted JavaScript and include compatible library declarations.
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(2,38): error TS2550: Property 'withResolvers' does not exist on type 'PromiseConstructor'. Do you need to change your target library? Try changing the 'lib' compiler option to 'es2024' or later. 6.0.3 TypeScript 6.0.3, run 21 October 2026: the same as 5.9.3. main.js(2,38): error TS2550: Property 'withResolvers' does not exist on type 'PromiseConstructor'. Do you need to change your target library? Try changing the 'lib' compiler option to 'es2024' or later. 7.0.2 TypeScript 7.0.2, run 21 October 2026: the same as 5.9.3. main.js(2,38): error TS2550: Property 'withResolvers' does not exist on type 'PromiseConstructor'. Do you need to change your target library? Try changing the 'lib' compiler option to 'es2024' or later. checked 21 October 2026 
const { promise, resolve } = Promise.withResolvers();error TS2550: Property 'withResolvers' does not exist on type 'PromiseConstructor'. Do you need to change your target library? Try changing the 'lib' compiler option to 'es2024' or later.

setTimeout(() => resolve("done"), 100);
console.log(await promise);
target es2022: an ES2024 method is not there.
jsconfig.json for this example 
{
  "compilerOptions": {
    "checkJs": true,
    "noEmit": true,
    "strict": true,
    "target": "es2022",
    "module": "nodenext",
    "types": []
  },
  "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 { promise, resolve } = Promise.withResolvers();

setTimeout(() => resolve("done"), 100);
console.log(await promise);
target es2024: Promise.withResolvers is declared.
jsconfig.json for this example 
{
  "compilerOptions": {
    "checkJs": true,
    "noEmit": true,
    "strict": true,
    "target": "es2024",
    "module": "nodenext",
    "types": []
  },
  "include": [
    "*.js"
  ]
}

What target does not do with noEmit

It does not make old runtimes understand new syntax: your files run exactly as written. If you write ??= or a class field and set target: "es2017", nothing reports that an ES2017 engine cannot parse them, because tsc would rewrite them if it wrote output. A few features it cannot rewrite are errors, such as BigInt literals below es2020 (TS2737). Treat target as a statement about your runtime that picks the library, not as a syntax compatibility check.

target and lib together

Without lib, target also brings the browser (DOM) declarations. Setting lib replaces that whole default, so with lib set, target no longer chooses any declarations. A Node.js project that wants ES2024 methods and no DOM can write "lib": ["es2024"] and leave target to module: "nodenext".

Gotchas

  • target: "esnext" follows whatever TypeScript considers the newest year, so it can let through a method your runtime does not have yet. A fixed year is more honest about your runtime.

  • jsconfig.json option

    lib

    lib picks the built-in declarations the checker knows: an ECMAScript year, and dom for browsers. Without dom there is no document, and no console either.

  • jsconfig.json option

    module

    module tells the checker which module system your .js files follow: Node's rules with nodenext, a bundler's with preserve. Set it, even with noEmit.

  • 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.

  • 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

    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.

  • TypeScript error

    TS1378: Top-level await with an older module setting

    TS1378 means await at the top of a module, with module or target set too old for it, often because module is missing. Set module to nodenext or es2022.

Sources

Last reviewed 20 October 2026.