Add no-sparse-arrays rule #2407
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why not name this the same as eslint and tslint-microsoft-contrib? |
src/rules/noArrayLiteralHoleRule.ts
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| for (const element of node.elements) { | ||
| if (utils.isOmittedExpression(element)) { | ||
| // Node has an empty range, so just use range starting at `element.pos`. | ||
| ctx.addFailureAt(element.pos, 1, Rule.FAILURE_STRING); |
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Unfortunately it's not that easy. You need to exclude array destructuring.
So you basically need test cases like:
[foo, , bar] = [];
[({foo: [, bar]})] = [];
[foo = [, 1]] = []; // should failHave a look at the tests for prefer-const, which does almost the same.
| @@ -0,0 +1,5 @@ | |||
| [1, , 3]; | |||
| ~ [Array has a missing element.] | |||
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add a test with trailing comma and one with multiple trailing commas
| ~ [Array has a missing element.] | ||
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| // Destructuring allowed. | ||
| const [x, , z] = arr; |
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That's only destructuring in declarations (ArrayBindingPattern). Destructuring in expression uses ArrayLiteralExpression, see my other comment above.
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| /** Traverse the LHS of an `=` expression, calling `cb` embedded default value, but ignoring binding patterns. */ | ||
| function traverseExpressionsInLHS(node: ts.Node, cb: (node: ts.Expression) => void): void { | ||
| switch (node.kind) { |
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you need to add a case for ts.SyntaxKind.ParethesizedExpression
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| [foo, , bar] = []; | ||
| [{foo: [, bar]}] = []; | ||
| [foo = [, 1]] = []; |
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can you add another test case like:
[foo = bar([,])] = [];
~[0]I know this works with your current implementation. Just to make sure we won't break it in the future.
PR checklist
Overview of change:
Added the
no-sparse-arraysrule, which warns on[1, , 3].CHANGELOG.md entry:
[new-rule]
no-sparse-arrays