No Array Constructor Index Assignment

SuggestionAuto-fixableRoblox

small-rules/no-array-constructor-index-assignment

Disallow new Array<T>() followed by contiguous index assignments; use an array literal instead.

Rationale

new Array<T>() then immediately writing arr[0] = a; arr[1] = b; right after is just a slow, ugly way to write [a, b]. And on roblox-ts specifically, you’re doing something that Luau does not like: unnecessary indexing.

This catches the pattern where you declare an empty array and fill it in by index right after. Auto-fixes to a literal when the assignments are contiguous and don’t reference the array itself. If you’re actually building a sparse array with gaps, this rule stays out of your way.

Diagnostic Messages

preferArrayLiteral

Use an array literal instead of new Array<T>() followed by index assignments.

Configuration

This rule does not accept options.

{
  "jsPlugins": [
    "@pobammer-ts/small-rules"
  ],
  "rules": {
    "small-rules/no-array-constructor-index-assignment": "error"
  }
}

Examples

array index assignment after construction

const samples = new Array<string>();
samples[0] = replacement;

After auto-fix

const samples = [replacement];

array literal initialization

const samples = [replacement];

Related Rules

No Array Constructor ElementsRelatedElement-form constructors and index-assignment fill patterns are adjacent Array construction smells.No Array Size AssignmentRelatedIndex fills and size/length appends are two non-push ways to build arrays that should collapse to literals/push.