prefer-set-has: Check Iterator#toArray() and String#split() (#2829)

Author: fisker

.github/workflows/update-snapshots.yml

@@ -19,7 +19,7 @@ jobs:
       - run: npm run lint
       - run: rm -rf test/snapshots
       # Force update snapshots, https://github.com/avajs/ava/discussions/2754
-      - run: npx c8 ava --update-snapshots
+      - run: npx ava --update-snapshots
         env:
           AVA_FORCE_CI: not-ci
       - uses: autofix-ci/action@v1

rules/prefer-set-has.js

@@ -9,22 +9,36 @@ const messages = {
 	[MESSAGE_ID_SUGGESTION]: 'Switch `{{name}}` to `Set`.',
 };
 
-const arrayMethodsReturnsArray = [
-	'concat',
+/*
+Some of these methods can be `Iterator`.
+
+Since `Iterator` don't have an `includes()` method, we are safe to assume they are array. Except `concat` and `slice` which can be a string: https://github.com/sindresorhus/eslint-plugin-unicorn/issues/2216
+*/
+const methodsReturnsArray = [
+	// `Array`
 	'copyWithin',
 	'fill',
 	'filter',
 	'flat',
 	'flatMap',
 	'map',
 	'reverse',
-	'slice',
 	'sort',
 	'splice',
 	'toReversed',
 	'toSorted',
 	'toSpliced',
 	'with',
+
+	// `Array` or `String` (unsafe)
+	'slice',
+	'concat',
+
+	// `String`
+	'split',
+
+	// `Iterator`
+	'toArray',
 ];
 
 const isIncludesCall = node =>
@@ -95,9 +109,9 @@ const create = context => {
 					optionalCall: false,
 					optionalMember: false,
 				})
-				// Array methods that return an array
+				// Methods that return an array
 				|| isMethodCall(parent.init, {
-					methods: arrayMethodsReturnsArray,
+					methods: methodsReturnsArray,
 					optionalCall: false,
 					optionalMember: false,
 				})

test/prefer-set-has.js

@@ -19,6 +19,8 @@ const methodsReturnsArray = [
 	'toSorted',
 	'toSpliced',
 	'with',
+	'toArray',
+	'split',
 ];
 
 test.snapshot({

test/snapshots/prefer-set-has.js.md

@@ -1346,7 +1346,63 @@ Generated by [AVA](https://avajs.dev).
       4 | }␊
     `
 
-## invalid(41): const foo = _([1,2,3]); const bar = foo.map(value => value); function unicorn() { return bar.includes(1); }
+## invalid(41): const foo = bar.toArray(); function unicorn() { return foo.includes(1); }
+
+> Input
+
+    `␊
+      1 | const foo = bar.toArray();␊
+      2 | function unicorn() {␊
+      3 | 	return foo.includes(1);␊
+      4 | }␊
+    `
+
+> Error 1/1
+
+    `␊
+    Message:␊
+    > 1 | const foo = bar.toArray();␊
+        |       ^^^ \`foo\` should be a \`Set\`, and use \`foo.has()\` to check existence or non-existence.␊
+      2 | function unicorn() {␊
+      3 | 	return foo.includes(1);␊
+      4 | }␊
+    ␊
+    Output:␊
+      1 | const foo = new Set(bar.toArray());␊
+      2 | function unicorn() {␊
+      3 | 	return foo.has(1);␊
+      4 | }␊
+    `
+
+## invalid(42): const foo = bar.split(); function unicorn() { return foo.includes(1); }
+
+> Input
+
+    `␊
+      1 | const foo = bar.split();␊
+      2 | function unicorn() {␊
+      3 | 	return foo.includes(1);␊
+      4 | }␊
+    `
+
+> Error 1/1
+
+    `␊
+    Message:␊
+    > 1 | const foo = bar.split();␊
+        |       ^^^ \`foo\` should be a \`Set\`, and use \`foo.has()\` to check existence or non-existence.␊
+      2 | function unicorn() {␊
+      3 | 	return foo.includes(1);␊
+      4 | }␊
+    ␊
+    Output:␊
+      1 | const foo = new Set(bar.split());␊
+      2 | function unicorn() {␊
+      3 | 	return foo.has(1);␊
+      4 | }␊
+    `
+
+## invalid(43): const foo = _([1,2,3]); const bar = foo.map(value => value); function unicorn() { return bar.includes(1); }
 
 > Input