---
source: crates/biome_js_analyze/tests/spec_tests.rs
expression: valid.jsonc
---
# Input
```cjs
class A { }
```

# Input
```cjs
class A { constructor(a, b = 0){ } }
```

# Diagnostics
```
valid.jsonc:1:11 lint/complexity/noUselessConstructor  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This constructor is unnecessary.
  
  > 1 │ class A { constructor(a, b = 0){ } }
      │           ^^^^^^^^^^^^^^^^^^^^^^^^
  
  i Unsafe fix: Remove the unnecessary constructor.
  
    1 │ class·A·{·constructor(a,·b·=·0){·}·}
      │           ------------------------- 

```

# Input
```cjs
class A { constructor(){ doSomething(); } }
```

# Input
```cjs
class A extends B { constructor(){} }
```

# Input
```cjs
class A extends B { constructor(){ super('foo'); } }
```

# Input
```cjs
class A extends B { constructor(foo, bar){ super(foo, bar, 1); } }
```

# Input
```cjs
class A extends B { constructor(){ super(); doSomething(); } }
```

# Input
```cjs
class A extends B { constructor(...args){ super(...args); doSomething(); } }
```

# Input
```cjs
class A { dummyMethod(){ doSomething(); } }
```

# Input
```cjs
class A extends B.C { constructor() { super(foo); } }
```

# Input
```cjs
class A extends B { constructor(a, b, c) { super(a, b); } }
```

# Input
```cjs
class A extends B { constructor(foo, bar){ super(foo); } }
```

# Input
```cjs
class A extends B { constructor(test) { super(); } }
```

# Input
```cjs
class A extends B { constructor() { foo; } }
```

# Input
```cjs
class A extends B { constructor(foo, bar) { super(bar); } }
```