consistent-target-and-lib

Disallow ES-versioned lib entries that are newer than the configured target.

Targeted pattern scope

The compilerOptions.target and compilerOptions.lib fields in any tsconfig*.json file.

What this rule reports

This rule reports when an explicit lib array contains an ES-versioned entry that is newer than the configured target.

Examples of configurations this rule reports:

target: "ES2020" with lib: ["ES2022", "DOM"]
target: "ES2018" with lib: ["ESNext"]

If lib is omitted entirely, or if lib is more conservative than target, this rule does not report.

Why this rule exists

The target option controls the syntax level TypeScript emits. The lib option controls which built-in APIs the type checker assumes are available at runtime. When lib is configured to a newer ES version than target, the type checker can accept APIs that are not a safe match for the configured output baseline.

This rule prevents that one-way mismatch.

❌ Incorrect

{
    "compilerOptions": {
        "target": "ES2020",
        "lib": ["ES2022", "DOM"]
    }
}

The type checker accepts ES2022 APIs even though the configured target is only ES2020.

✅ Correct

{
    "compilerOptions": {
        "target": "ES2022",
        "lib": ["ES2022", "DOM"]
    }
}

Or use a more conservative lib:

{
    "compilerOptions": {
        "target": "ES2022",
        "lib": ["ES2020", "DOM"]
    }
}

When not to use it

Disable this rule if you intentionally model newer runtime APIs than the configured target because the environment guarantees polyfills, or if you do not want to enforce this one-way compatibility check.

Package documentation

Rule catalog ID: R003

Targeted pattern scope​

What this rule reports​

Why this rule exists​

❌ Incorrect​

✅ Correct​

When not to use it​

Package documentation​

Further reading​