---
source: crates/biome_js_analyze/tests/spec_tests.rs
expression: thisBeforeSuper.js
---
# Input
```jsx
// valid
class B extends A {
    constructor() {
        super();
        this.field = "value";
    }
}

// valid
class C extends A {
    constructor(cond) {
        if (cond) {
            super(true);
        } else {
            super(false);
        }
        this.field = "value";
    }
}

// invalid
class D extends A {
    constructor() {
        this.field = "value";
        super();
    }
}

// invalid
class E extends A {
    constructor(cond) {
        this.field = "value";
        if (cond) {
            super(true);
        } else {
            super(false);
        }
    }
}

// invalid
class F extends A {
    constructor(cond) {
        if (cond) {
            super(true);
        }
        this.field = "value";
    }
}

// invalid
class G extends A {
    constructor(condA, condB) {
        try {
            super();
        } catch {
            this.prop = 0;
        }
    }
}

// invalid
class G extends A {
    constructor(condA, condB) {
        try {
            this.prop = 0;
        } catch {
            super();
        }
    }
}

```

# Diagnostics
```
thisBeforeSuper.js:23:5 lint/correctness/noUnreachableSuper ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This constructor has code paths accessing `this` without calling `super()` first.
  
    21 │ // invalid
    22 │ class D extends A {
  > 23 │     constructor() {
       │     ^^^^^^^^^^^^^^^
  > 24 │         this.field = "value";
  > 25 │         super();
  > 26 │     }
       │     ^
    27 │ }
    28 │ 
  
  i `this` is accessed here:
  
    22 │ class D extends A {
    23 │     constructor() {
  > 24 │         this.field = "value";
       │         ^^^^
    25 │         super();
    26 │     }
  
  i If this is intentional, add an explicit throw statement in unsupported paths.
  

```

```
thisBeforeSuper.js:31:5 lint/correctness/noUnreachableSuper ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This constructor has code paths accessing `this` without calling `super()` first.
  
    29 │ // invalid
    30 │ class E extends A {
  > 31 │     constructor(cond) {
       │     ^^^^^^^^^^^^^^^^^^^
  > 32 │         this.field = "value";
        ...
  > 37 │         }
  > 38 │     }
       │     ^
    39 │ }
    40 │ 
  
  i `this` is accessed here:
  
    30 │ class E extends A {
    31 │     constructor(cond) {
  > 32 │         this.field = "value";
       │         ^^^^
    33 │         if (cond) {
    34 │             super(true);
  
  i If this is intentional, add an explicit throw statement in unsupported paths.
  

```

```
thisBeforeSuper.js:43:5 lint/correctness/noUnreachableSuper ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This constructor has code paths accessing `this` without calling `super()` first.
  
    41 │ // invalid
    42 │ class F extends A {
  > 43 │     constructor(cond) {
       │     ^^^^^^^^^^^^^^^^^^^
  > 44 │         if (cond) {
  > 45 │             super(true);
  > 46 │         }
  > 47 │         this.field = "value";
  > 48 │     }
       │     ^
    49 │ }
    50 │ 
  
  i `this` is accessed here:
  
    45 │             super(true);
    46 │         }
  > 47 │         this.field = "value";
       │         ^^^^
    48 │     }
    49 │ }
  
  i If this is intentional, add an explicit throw statement in unsupported paths.
  

```

```
thisBeforeSuper.js:53:5 lint/correctness/noUnreachableSuper ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This constructor has code paths accessing `this` without calling `super()` first.
  
    51 │ // invalid
    52 │ class G extends A {
  > 53 │     constructor(condA, condB) {
       │     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  > 54 │         try {
        ...
  > 58 │         }
  > 59 │     }
       │     ^
    60 │ }
    61 │ 
  
  i `this` is accessed here:
  
    55 │             super();
    56 │         } catch {
  > 57 │             this.prop = 0;
       │             ^^^^
    58 │         }
    59 │     }
  
  i If this is intentional, add an explicit throw statement in unsupported paths.
  

```

```
thisBeforeSuper.js:64:5 lint/correctness/noUnreachableSuper ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This constructor has code paths accessing `this` without calling `super()` first.
  
    62 │ // invalid
    63 │ class G extends A {
  > 64 │     constructor(condA, condB) {
       │     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  > 65 │         try {
        ...
  > 69 │         }
  > 70 │     }
       │     ^
    71 │ }
    72 │ 
  
  i `this` is accessed here:
  
    64 │     constructor(condA, condB) {
    65 │         try {
  > 66 │             this.prop = 0;
       │             ^^^^
    67 │         } catch {
    68 │             super();
  
  i If this is intentional, add an explicit throw statement in unsupported paths.
  

```