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small-rules

No Array Size Assignment

ErrorAuto-fixableRoblox
small-rules/no-array-size-assignment

Disallow array append assignments using array[array.size()] = value (roblox-ts) or array[array.length] = value (standard) and prefer push-based appends.

Rationale

array[array.size()] = value works but it’s goofy. Just use array.push(value) – clearer, faster, and it matches what every JS dev expects. Or even better… use array[size++] = value like what was mentioned in the rationale for no-increment-decrement.

This flags any assignment where the index is the array’s own size. Auto-fixes to .push() when the target is simple. If the assignment references the array in a way that would change semantics (like array[array.size()] = array[array.size() - 1]), it won’t touch it. allowAutofix is off by default so you can review each one.

Diagnostic Messages

usePush
Do not append with array[array.size()] = value or array[array.length] = value. Use array.push(value) instead.

Configuration

This rule accepts one options object after the severity.

allowAutofixOptional

Allow the fixer to replace safe append assignments with array.push(value).

Type
boolean
Default
false
environmentOptional

Array environment mode: 'roblox-ts' checks array[array.size()]; 'standard' checks array[array.length].

Type
"roblox-ts" | "standard"
Default
roblox-ts
{
  "jsPlugins": [
    "@pobammer-ts/small-rules"
  ],
  "rules": {
    "small-rules/no-array-size-assignment": [
      "error",
      {
        "allowAutofix": false,
        "environment": "roblox-ts"
      }
    ]
  }
}

Examples

array size index assignment
array[array.size()] = value;

After auto-fix

array.push(value);
append with push
array.push(value);
No Array Constructor ElementsRelatedConstructor initialization and size/length append assignment are both roblox-ts array construction style.No Array Constructor Index AssignmentRelatedIndex fills and size/length appends are two non-push ways to build arrays that should collapse to literals/push.