---
source: crates/biome_js_analyze/tests/spec_tests.rs
expression: invalidBindingPattern.js
---
# Input
```jsx
function f({ b = a, a = 0 }) {}
function f([b = a, a = 0]) {}
function f({ x: [b = a, { a = 0 }] }) {}
function f({ a = a }) {}
{
	const { b = a, a = 0 } = {};
}
{
	const [b = a, a = 0] = {};
}
{
	const {
		x: [b = a, { a = 0 }],
	} = {};
}
```

# Diagnostics
```
invalidBindingPattern.js:1:18 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━━

  ! This variable is used before its declaration.
  
  > 1 │ function f({ b = a, a = 0 }) {}
      │                  ^
    2 │ function f([b = a, a = 0]) {}
    3 │ function f({ x: [b = a, { a = 0 }] }) {}
  
  i The variable is declared here:
  
  > 1 │ function f({ b = a, a = 0 }) {}
      │                     ^
    2 │ function f([b = a, a = 0]) {}
    3 │ function f({ x: [b = a, { a = 0 }] }) {}
  

```

```
invalidBindingPattern.js:2:17 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━━

  ! This variable is used before its declaration.
  
    1 │ function f({ b = a, a = 0 }) {}
  > 2 │ function f([b = a, a = 0]) {}
      │                 ^
    3 │ function f({ x: [b = a, { a = 0 }] }) {}
    4 │ function f({ a = a }) {}
  
  i The variable is declared here:
  
    1 │ function f({ b = a, a = 0 }) {}
  > 2 │ function f([b = a, a = 0]) {}
      │                    ^
    3 │ function f({ x: [b = a, { a = 0 }] }) {}
    4 │ function f({ a = a }) {}
  

```

```
invalidBindingPattern.js:3:22 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━━

  ! This variable is used before its declaration.
  
    1 │ function f({ b = a, a = 0 }) {}
    2 │ function f([b = a, a = 0]) {}
  > 3 │ function f({ x: [b = a, { a = 0 }] }) {}
      │                      ^
    4 │ function f({ a = a }) {}
    5 │ {
  
  i The variable is declared here:
  
    1 │ function f({ b = a, a = 0 }) {}
    2 │ function f([b = a, a = 0]) {}
  > 3 │ function f({ x: [b = a, { a = 0 }] }) {}
      │                           ^
    4 │ function f({ a = a }) {}
    5 │ {
  

```

```
invalidBindingPattern.js:4:18 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━━

  ! This variable is used before its declaration.
  
    2 │ function f([b = a, a = 0]) {}
    3 │ function f({ x: [b = a, { a = 0 }] }) {}
  > 4 │ function f({ a = a }) {}
      │                  ^^
    5 │ {
    6 │ 	const { b = a, a = 0 } = {};
  
  i The variable is declared here:
  
    2 │ function f([b = a, a = 0]) {}
    3 │ function f({ x: [b = a, { a = 0 }] }) {}
  > 4 │ function f({ a = a }) {}
      │              ^
    5 │ {
    6 │ 	const { b = a, a = 0 } = {};
  

```

```
invalidBindingPattern.js:6:14 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━━

  ! This variable is used before its declaration.
  
    4 │ function f({ a = a }) {}
    5 │ {
  > 6 │ 	const { b = a, a = 0 } = {};
      │ 	            ^
    7 │ }
    8 │ {
  
  i The variable is declared here:
  
    4 │ function f({ a = a }) {}
    5 │ {
  > 6 │ 	const { b = a, a = 0 } = {};
      │ 	               ^
    7 │ }
    8 │ {
  

```

```
invalidBindingPattern.js:9:13 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━━

  ! This variable is used before its declaration.
  
     7 │ }
     8 │ {
   > 9 │ 	const [b = a, a = 0] = {};
       │ 	           ^
    10 │ }
    11 │ {
  
  i The variable is declared here:
  
     7 │ }
     8 │ {
   > 9 │ 	const [b = a, a = 0] = {};
       │ 	              ^
    10 │ }
    11 │ {
  

```

```
invalidBindingPattern.js:13:11 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━

  ! This variable is used before its declaration.
  
    11 │ {
    12 │ 	const {
  > 13 │ 		x: [b = a, { a = 0 }],
       │ 		        ^
    14 │ 	} = {};
    15 │ }
  
  i The variable is declared here:
  
    11 │ {
    12 │ 	const {
  > 13 │ 		x: [b = a, { a = 0 }],
       │ 		             ^
    14 │ 	} = {};
    15 │ }
  

```