# no-sparse-arrays

Disallow sparse arrays.

Sparse arrays are arrays with empty slots, they are denoted by extra commas, such as:

let foo = [,,];
let foo = [bar,, baz];

Sparse elements will be filled in as undefined elements and count towards array length. This is often a typo or is hard to comprehend and an explicit method should be used.

# Invalid Code Examples

let foo = [,];
let bar = [foo,, bar];

[,]

[...2,, 3]

[4,,]

[1, 2]

[3,]

Source (opens new window)