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:
js
// These are the 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 the 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:
js
// 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 using the config file or in the CLI, you can use:
json
{
"rules": {
"no-useless-call": "error"
}
}ts
import { defineConfig } from "oxlint";
export default defineConfig({
rules: {
"no-useless-call": "error",
},
});bash
oxlint --deny no-useless-callVersion
This rule was added in v0.15.9.