eslint/no-useless-call Perf

What it does

Disallow unnecessary calls to .call() and .apply()

Why is this bad?

Function.prototype.call() and Function.prototype.apply() are slower than the normal function invocation.

This rule compares code statically to check whether or not thisArg is changed. So if the code about thisArg is a dynamic expression, this rule cannot judge correctly.

Examples

Examples of incorrect code for this rule:

// These are same as `foo(1, 2, 3);`
foo.call(undefined, 1, 2, 3);
foo.apply(undefined, [1, 2, 3]);
foo.call(null, 1, 2, 3);
foo.apply(null, [1, 2, 3]);

// These are same as `obj.foo(1, 2, 3);`
obj.foo.call(obj, 1, 2, 3);
obj.foo.apply(obj, [1, 2, 3]);

Examples of correct code for this rule:

// The `this` binding is different.
foo.call(obj, 1, 2, 3);
foo.apply(obj, [1, 2, 3]);
obj.foo.call(null, 1, 2, 3);
obj.foo.apply(null, [1, 2, 3]);
obj.foo.call(otherObj, 1, 2, 3);
obj.foo.apply(otherObj, [1, 2, 3]);

// The argument list is variadic.
// Those are warned by the `prefer-spread` rule.
foo.apply(undefined, args);
foo.apply(null, args);
obj.foo.apply(obj, args);

How to use

To enable this rule in the CLI or using the config file, you can use:

CLI

oxlint --deny no-useless-call

Config (.oxlintrc.json)

{
  "rules": {
    "no-useless-call": "error"
  }
}

References

• Rule Source