prefer-at: Improve fix (#1901)

sindresorhus · Sep 19, 2022 · 1c457bb · 1c457bb
1 parent 70e5bdd
commit 1c457bb
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Showing 4 changed files with 112 additions and 25 deletions.
diff --git a/rules/prefer-at.js b/rules/prefer-at.js
@@ -179,6 +179,25 @@ function create(context) {
 					yield removeLengthNode(lengthNode, fixer, sourceCode);
 				}
 
+				// Only remove space for `foo[foo.length - 1]`
+				if (
+					indexNode.type === 'BinaryExpression'
+					&& indexNode.operator === '-'
+					&& indexNode.left === lengthNode
+					&& indexNode.right.type === 'Literal'
+					&& /^\d+$/.test(indexNode.right.raw)
+				) {
+					const numberNode = indexNode.right;
+					const tokenBefore = sourceCode.getTokenBefore(numberNode);
+					if (
+						tokenBefore.type === 'Punctuator'
+						&& tokenBefore.value === '-'
+						&& /^\s+$/.test(sourceCode.text.slice(tokenBefore.range[1], numberNode.range[0]))
+					) {
+						yield fixer.removeRange([tokenBefore.range[1], numberNode.range[0]]);
+					}
+				}
+
 				const openingBracketToken = sourceCode.getTokenBefore(indexNode, isOpeningBracketToken);
 				yield fixer.replaceText(openingBracketToken, '.at(');
 

diff --git a/test/prefer-at.mjs b/test/prefer-at.mjs
@@ -21,6 +21,10 @@ test.snapshot({
 	],
 	invalid: [
 		'array[array.length - 1];',
+		'array[array.length -1];',
+		'array[array.length - /* comment */ 1];',
+		'array[array.length - 1.];',
+		'array[array.length - 0b1];',
 		'array[array.length - 9];',
 		'array[0][array[0].length - 1];',
 		'array[(( array.length )) - 1];',

diff --git a/test/snapshots/prefer-at.mjs.md b/test/snapshots/prefer-at.mjs.md
@@ -10,7 +10,7 @@ Generated by [AVA](https://avajs.dev).
 > Output
 
     `␊
-      1 | array.at(- 1);␊
+      1 | array.at(-1);␊
     `
 
 > Error 1/1
@@ -21,12 +21,76 @@ Generated by [AVA](https://avajs.dev).
     `
 
 ## Invalid #2
+      1 | array[array.length -1];
+
+> Output
+
+    `␊
+      1 | array.at(-1);␊
+    `
+
+> Error 1/1
+
+    `␊
+    > 1 | array[array.length -1];␊
+        |       ^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
+    `
+
+## Invalid #3
+      1 | array[array.length - /* comment */ 1];
+
+> Output
+
+    `␊
+      1 | array.at(- /* comment */ 1);␊
+    `
+
+> Error 1/1
+
+    `␊
+    > 1 | array[array.length - /* comment */ 1];␊
+        |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
+    `
+
+## Invalid #4
+      1 | array[array.length - 1.];
+
+> Output
+
+    `␊
+      1 | array.at(- 1.);␊
+    `
+
+> Error 1/1
+
+    `␊
+    > 1 | array[array.length - 1.];␊
+        |       ^^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
+    `
+
+## Invalid #5
+      1 | array[array.length - 0b1];
+
+> Output
+
+    `␊
+      1 | array.at(- 0b1);␊
+    `
+
+> Error 1/1
+
+    `␊
+    > 1 | array[array.length - 0b1];␊
+        |       ^^^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
+    `
+
+## Invalid #6
       1 | array[array.length - 9];
 
 > Output
 
     `␊
-      1 | array.at(- 9);␊
+      1 | array.at(-9);␊
     `
 
 > Error 1/1
@@ -36,13 +100,13 @@ Generated by [AVA](https://avajs.dev).
         |       ^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
     `
 
-## Invalid #3
+## Invalid #7
       1 | array[0][array[0].length - 1];
 
 > Output
 
     `␊
-      1 | array[0].at(- 1);␊
+      1 | array[0].at(-1);␊
     `
 
 > Error 1/1
@@ -52,13 +116,13 @@ Generated by [AVA](https://avajs.dev).
         |          ^^^^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
     `
 
-## Invalid #4
+## Invalid #8
       1 | array[(( array.length )) - 1];
 
 > Output
 
     `␊
-      1 | array.at(- 1);␊
+      1 | array.at(-1);␊
     `
 
 > Error 1/1
@@ -68,7 +132,7 @@ Generated by [AVA](https://avajs.dev).
         |       ^^^^^^^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
     `
 
-## Invalid #5
+## Invalid #9
       1 | array[array.length - (( 1 ))];
 
 > Output
@@ -84,13 +148,13 @@ Generated by [AVA](https://avajs.dev).
         |       ^^^^^^^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
     `
 
-## Invalid #6
+## Invalid #10
       1 | array[(( array.length - 1 ))];
 
 > Output
 
     `␊
-      1 | array.at((( - 1 )));␊
+      1 | array.at((( -1 )));␊
     `
 
 > Error 1/1
@@ -100,13 +164,13 @@ Generated by [AVA](https://avajs.dev).
         |          ^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
     `
 
-## Invalid #7
+## Invalid #11
       1 | (( array ))[array.length - 1];
 
 > Output
 
     `␊
-      1 | (( array )).at(- 1);␊
+      1 | (( array )).at(-1);␊
     `
 
 > Error 1/1
@@ -116,13 +180,13 @@ Generated by [AVA](https://avajs.dev).
         |             ^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
     `
 
-## Invalid #8
+## Invalid #12
       1 | (( array[array.length - 1] ));
 
 > Output
 
     `␊
-      1 | (( array.at(- 1) ));␊
+      1 | (( array.at(-1) ));␊
     `
 
 > Error 1/1
@@ -132,13 +196,13 @@ Generated by [AVA](https://avajs.dev).
         |          ^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
     `
 
-## Invalid #9
+## Invalid #13
       1 | array[array.length - 1].pop().shift()[0];
 
 > Output
 
     `␊
-      1 | array.at(- 1).pop().shift()[0];␊
+      1 | array.at(-1).pop().shift()[0];␊
     `
 
 > Error 1/1
@@ -148,13 +212,13 @@ Generated by [AVA](https://avajs.dev).
         |       ^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
     `
 
-## Invalid #10
+## Invalid #14
       1 | a = array[array.length - 1]
 
 > Output
 
     `␊
-      1 | a = array.at(- 1)␊
+      1 | a = array.at(-1)␊
     `
 
 > Error 1/1
@@ -164,13 +228,13 @@ Generated by [AVA](https://avajs.dev).
         |           ^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
     `
 
-## Invalid #11
+## Invalid #15
       1 | const a = array[array.length - 1]
 
 > Output
 
     `␊
-      1 | const a = array.at(- 1)␊
+      1 | const a = array.at(-1)␊
     `
 
 > Error 1/1
@@ -180,13 +244,13 @@ Generated by [AVA](https://avajs.dev).
         |                 ^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
     `
 
-## Invalid #12
+## Invalid #16
       1 | const {a = array[array.length - 1]} = {}
 
 > Output
 
     `␊
-      1 | const {a = array.at(- 1)} = {}␊
+      1 | const {a = array.at(-1)} = {}␊
     `
 
 > Error 1/1
@@ -196,13 +260,13 @@ Generated by [AVA](https://avajs.dev).
         |                  ^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
     `
 
-## Invalid #13
+## Invalid #17
       1 | typeof array[array.length - 1]
 
 > Output
 
     `␊
-      1 | typeof array.at(- 1)␊
+      1 | typeof array.at(-1)␊
     `
 
 > Error 1/1
@@ -212,7 +276,7 @@ Generated by [AVA](https://avajs.dev).
         |              ^^^^^^^^^^^^^^^^ Prefer \`.at(…)\` over \`[….length - index]\`.␊
     `
 
-## Invalid #14
+## Invalid #18
       1 | function foo() {return arguments[arguments.length - 1]}
 
 > Error 1/1
@@ -1108,7 +1172,7 @@ Generated by [AVA](https://avajs.dev).
 > Output
 
     `␊
-      1 | array.at(- 1)␊
+      1 | array.at(-1)␊
     `
 
 > Error 1/1

diff --git a/test/snapshots/prefer-at.mjs.snap b/test/snapshots/prefer-at.mjs.snap