Upgrading to TypeScript 7? 9 tools tested (ESLint, Jest, ts-node)

TypeScript 7 is the compiler rewritten in Go, and it shipped on July 8, 2026 without a JavaScript API. The tsc command works as before; anything that imports typescript as a library does not. I took one small project and ran the same eleven tasks against three setups to find out exactly what that means in practice.

The results

The setup that fixed everything

npm install -D "@typescript/native@npm:typescript@7.0.2" "typescript@npm:@typescript/typescript6@^6.0.2"

{
  "devDependencies": {
    "@typescript/native": "npm:typescript@^7.0.2",
    "typescript": "npm:@typescript/typescript6@^6.0.2"
  }
}

Tool by tool

The exact error each tool printed on plain TypeScript 7.0.2, re-run on September 25 with the versions in the table. Every one of them passed after switching to the side-by-side setup above.

ts-jest and Jest with TypeScript 7

ts-jest 29.4.13 on Jest 30.5.2 stops before running a single test, and its message already names the fix:

● Test suite failed to run
  The TypeScript compiler "typescript" (version 7.0.2) does not expose the JavaScript compiler API required by ts-jest. To use TypeScript 7 for project type-checking, install it as "@typescript/native" and alias "@typescript/typescript6" as "typescript" for ts-jest.

On the side-by-side setup: Tests: 1 passed, 1 total.

ts-loader and webpack with TypeScript 7

webpack 5.111.1 still writes main.js, but ts-loader 9.6.2 fails the build:

ERROR in ./src/index.ts
Module build failed (from ./node_modules/ts-loader/index.js):
TypeError: Cannot read properties of undefined (reading 'fileExists')

On the side-by-side setup: compiled successfully.

ESLint (typescript-eslint) with TypeScript 7

ESLint 10.11.0 with typescript-eslint 8.70.1 refuses to lint at all:

Error: typescript-eslint does not support TS 7.0.

On the side-by-side setup: npx eslint src exited 0. More on this one, including the npm error you usually hit first: typescript-eslint does not support TS 7.0.

TypeDoc with TypeScript 7

TypeDoc 0.28.20 crashes while loading, before reading your code:

TypeError: Cannot read properties of undefined (reading 'PropertyDeclaration')

On the side-by-side setup: the HTML docs generated normally.

ts-node with TypeScript 7

ts-node 10.9.2 crashes on its first step, reading tsconfig.json:

TypeError: Cannot read properties of undefined (reading 'fileExists')

On the side-by-side setup it printed the script’s output. The full write-up: ts-node’s fileExists crash.

tsx, Vitest and ts-morph with TypeScript 7

All three worked on plain TypeScript 7 in the original run, because none of them loads your installed typescript package at run time (see below). If Vitest fails after the upgrade, check the --legacy-peer-deps trap further down first.

Why exactly these five broke

Every failure traces to the same fact. On TypeScript 7.0.2 the package exports two things:

node -p "Object.keys(require('typescript'))"
# [ 'version', 'versionMajorMinor' ]

A tool that calls into the compiler hits undefined on its first real call, and the message depends on which property it reaches for first:

• ts-node and ts-loader read ts.sys.fileExists while loading tsconfig.json, so both die with the identical Cannot read properties of undefined (reading 'fileExists').
• TypeDoc reaches for ts.SyntaxKind.PropertyDeclaration: Cannot read properties of undefined (reading 'PropertyDeclaration').
• ts-jest and typescript-eslint check first and fail politely, with messages that name the problem.

The four that survived don’t import TypeScript at run time at all. tsx and Vitest strip types with their own transformers (esbuild for tsx, Vite’s for Vitest), and ts-morph bundles its own copy (@ts-morph/common/dist/typescript.js), so the version you install doesn’t matter to it.

The install error comes first

In a real project you don’t get as far as the runtime errors, because npm refuses first. Three tools declare ranges that exclude 7:

That last pair is the dangerous kind: the ranges say yes, so npm installs quietly and the failure arrives later, at run time.

The --legacy-peer-deps trap

The first answer people find for ERESOLVE is --legacy-peer-deps. It did get TypeScript 7 installed. It also broke Vitest:

Error [ERR_MODULE_NOT_FOUND]: Cannot find package 'vite' imported from
.../node_modules/vitest/dist/chunks/index.DzobfTyw.js

That flag doesn’t only skip the conflicting check; it skips installing every peer dependency, and Vitest relies on npm to bring in Vite as one. Adding Vite back by hand made Vitest pass on TypeScript 7 again, which is how I know it was the flag and not the compiler.

Should you upgrade?

• If you only run tsc (plus tsx, Vitest or a bundler), plain TypeScript 7 worked in every check here.
• If you use any tool in the ❌ rows, use the side-by-side setup. It’s the supported path until TypeScript 7.1 ships its new API, and TypeScript’s team says 7.1’s API will be different, so each of these tools will need its own update even then.
• Don’t pin typescript@6 and forget it. It works, but you give up the new compiler for your builds, which is the whole point of 7.

The individual errors have their own write-ups: ts-node’s fileExists crash and typescript-eslint “does not support TS 7.0”.

Frameworks were tested separately, from their own starters: Does Next.js, Angular, Vue or NestJS work with TypeScript 7?

The whole upgrade, including the tsconfig options TypeScript 7 rejects: TypeScript 7 migration guide.

Run it yourself

The setup is on GitHub with scripts that break it and restore it, so you can watch each failure and fix on your own machine:

git clone https://github.com/nils44344/node-ts-error-repros
cd node-ts-error-repros/05-typescript-7-side-by-side
npm install && npm run all

How this was measured

• One project, three setups, nothing else changed: the same tsconfig.json, source, test files and tool versions, with only the typescript entries in package.json differing.
• Eleven tasks per setup: tsc --version, tsc --noEmit, ts-node, tsx, Jest with ts-jest, ESLint with and without type information, a ts-morph script, TypeDoc, Vitest, and a webpack build with ts-loader.
• Strict install first, to record what npm refuses, then --legacy-peer-deps so the tools could be run and their own errors recorded.
• Every failure was chased to its cause. Vitest’s apparent failure was traced to the install flag and re-tested before it was left out of the TypeScript 7 column.

Limits of this test

• One small project on Windows. Large monorepos, project references and custom transformers weren’t tested.
• Framework CLIs weren’t included. Angular, Vue’s language tools and Svelte’s checker all depend on the compiler API and are likely affected, but I haven’t run them, so they aren’t in the table.
• This is a snapshot of September 2026. TypeScript 7.1 and new releases of these tools will change the answers; this entry will be re-tested when they land.