diff --git a/packages/eslint-plugin/docs/rules/prefer-optional-chain.md b/packages/eslint-plugin/docs/rules/prefer-optional-chain.md
index 1f42754e0f75..4d0e0871c73b 100644
--- a/packages/eslint-plugin/docs/rules/prefer-optional-chain.md
+++ b/packages/eslint-plugin/docs/rules/prefer-optional-chain.md
@@ -22,6 +22,10 @@ function myFunc(foo: T | null) {
function myFunc(foo: T | null) {
return foo && foo.a && foo.a.b && foo.a.b.c;
}
+// or
+function myFunc(foo: T | null) {
+ return (((foo || {}).a || {}).b || {}).c;
+}
function myFunc(foo: T | null) {
return foo?.['a']?.b?.c;
@@ -57,6 +61,9 @@ foo && foo.a && foo.a.b && foo.a.b.c;
foo && foo['a'] && foo['a'].b && foo['a'].b.c;
foo && foo.a && foo.a.b && foo.a.b.method && foo.a.b.method();
+(((foo || {}).a || {}).b {}).c;
+(((foo || {})['a'] || {}).b {}).c;
+
// this rule also supports converting chained strict nullish checks:
foo &&
foo.a != null &&
diff --git a/packages/eslint-plugin/src/rules/prefer-optional-chain.ts b/packages/eslint-plugin/src/rules/prefer-optional-chain.ts
index 109deaa6d60d..b3815e09ef97 100644
--- a/packages/eslint-plugin/src/rules/prefer-optional-chain.ts
+++ b/packages/eslint-plugin/src/rules/prefer-optional-chain.ts
@@ -1,5 +1,7 @@
-import { AST_NODE_TYPES, TSESTree, TSESLint } from '@typescript-eslint/utils';
+import * as ts from 'typescript';
import * as util from '../util';
+import { AST_NODE_TYPES, TSESTree, TSESLint } from '@typescript-eslint/utils';
+import { isBinaryExpression } from 'tsutils';
type ValidChainTarget =
| TSESTree.BinaryExpression
@@ -47,7 +49,68 @@ export default util.createRule({
defaultOptions: [],
create(context) {
const sourceCode = context.getSourceCode();
+ const parserServices = util.getParserServices(context, true);
+
return {
+ 'LogicalExpression[operator="||"], LogicalExpression[operator="??"]'(
+ node: TSESTree.LogicalExpression,
+ ): void {
+ const leftNode = node.left;
+ const rightNode = node.right;
+ const parentNode = node.parent;
+ const isRightNodeAnEmptyObjectLiteral =
+ rightNode.type === AST_NODE_TYPES.ObjectExpression &&
+ rightNode.properties.length === 0;
+ if (
+ !isRightNodeAnEmptyObjectLiteral ||
+ !parentNode ||
+ parentNode.type !== AST_NODE_TYPES.MemberExpression ||
+ parentNode.optional
+ ) {
+ return;
+ }
+
+ function isLeftSideLowerPrecedence(): boolean {
+ const logicalTsNode = parserServices.esTreeNodeToTSNodeMap.get(node);
+
+ const leftTsNode = parserServices.esTreeNodeToTSNodeMap.get(leftNode);
+ const operator = isBinaryExpression(logicalTsNode)
+ ? logicalTsNode.operatorToken.kind
+ : ts.SyntaxKind.Unknown;
+ const leftPrecedence = util.getOperatorPrecedence(
+ leftTsNode.kind,
+ operator,
+ );
+
+ return leftPrecedence < util.OperatorPrecedence.LeftHandSide;
+ }
+ context.report({
+ node: parentNode,
+ messageId: 'optionalChainSuggest',
+ suggest: [
+ {
+ messageId: 'optionalChainSuggest',
+ fix: (fixer): TSESLint.RuleFix => {
+ const leftNodeText = sourceCode.getText(leftNode);
+ // Any node that is made of an operator with higher or equal precedence,
+ const maybeWrappedLeftNode = isLeftSideLowerPrecedence()
+ ? `(${leftNodeText})`
+ : leftNodeText;
+ const propertyToBeOptionalText = sourceCode.getText(
+ parentNode.property,
+ );
+ const maybeWrappedProperty = parentNode.computed
+ ? `[${propertyToBeOptionalText}]`
+ : propertyToBeOptionalText;
+ return fixer.replaceTextRange(
+ parentNode.range,
+ `${maybeWrappedLeftNode}?.${maybeWrappedProperty}`,
+ );
+ },
+ },
+ ],
+ });
+ },
[[
'LogicalExpression[operator="&&"] > Identifier',
'LogicalExpression[operator="&&"] > MemberExpression',
diff --git a/packages/eslint-plugin/src/util/index.ts b/packages/eslint-plugin/src/util/index.ts
index a83198807a67..b2932466388d 100644
--- a/packages/eslint-plugin/src/util/index.ts
+++ b/packages/eslint-plugin/src/util/index.ts
@@ -4,6 +4,7 @@ export * from './astUtils';
export * from './collectUnusedVariables';
export * from './createRule';
export * from './getFunctionHeadLoc';
+export * from './getOperatorPrecedence';
export * from './getThisExpression';
export * from './getWrappingFixer';
export * from './misc';
diff --git a/packages/eslint-plugin/tests/rules/prefer-optional-chain.test.ts b/packages/eslint-plugin/tests/rules/prefer-optional-chain.test.ts
index d6ac19abb896..2b004e9d7a9c 100644
--- a/packages/eslint-plugin/tests/rules/prefer-optional-chain.test.ts
+++ b/packages/eslint-plugin/tests/rules/prefer-optional-chain.test.ts
@@ -146,6 +146,22 @@ const baseCases = [
ruleTester.run('prefer-optional-chain', rule, {
valid: [
+ 'foo || {};',
+ 'foo || ({} as any);',
+ '(foo || {})?.bar;',
+ '(foo || { bar: 1 }).bar;',
+ '(undefined && (foo || {})).bar;',
+ 'foo ||= bar;',
+ 'foo ||= bar || {};',
+ 'foo ||= bar?.baz;',
+ 'foo ||= bar?.baz || {};',
+ 'foo ||= bar?.baz?.buzz;',
+ '(foo1 ? foo2 : foo3 || {}).foo4;',
+ '(foo = 2 || {}).bar;',
+ 'func(foo || {}).bar;',
+ 'foo ?? {};',
+ '(foo ?? {})?.bar;',
+ 'foo ||= bar ?? {};',
'foo && bar;',
'foo && foo;',
'foo || bar;',
@@ -501,5 +517,631 @@ foo?.bar(/* comment */a,
},
},
},
+ {
+ code: '(foo || {}).bar;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 16,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: 'foo?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`(foo || ({})).bar;`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 18,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: 'foo?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`(await foo || {}).bar;`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 22,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(await foo)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '(foo1?.foo2 || {}).foo3;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 24,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: 'foo1?.foo2?.foo3;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '((() => foo())() || {}).bar;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 28,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(() => foo())()?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: 'const foo = (bar || {}).baz;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 13,
+ endColumn: 28,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: 'const foo = bar?.baz;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '(foo.bar || {})[baz];',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 21,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: 'foo.bar?.[baz];',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '((foo1 || {}).foo2 || {}).foo3;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 31,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(foo1 || {}).foo2?.foo3;',
+ },
+ ],
+ },
+ {
+ messageId: 'optionalChainSuggest',
+ column: 2,
+ endColumn: 19,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(foo1?.foo2 || {}).foo3;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '(foo || undefined || {}).bar;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(foo || undefined)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '(foo() || bar || {}).baz;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 25,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(foo() || bar)?.baz;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '((foo1 ? foo2 : foo3) || {}).foo4;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 34,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(foo1 ? foo2 : foo3)?.foo4;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`if (foo) { (foo || {}).bar; }`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 12,
+ endColumn: 27,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: noFormat`if (foo) { foo?.bar; }`,
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`if ((foo || {}).bar) { foo.bar; }`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 5,
+ endColumn: 20,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: noFormat`if (foo?.bar) { foo.bar; }`,
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`(undefined && foo || {}).bar;`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 29,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(undefined && foo)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '(foo ?? {}).bar;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 16,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: 'foo?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`(foo ?? ({})).bar;`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 18,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: 'foo?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`(await foo ?? {}).bar;`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 22,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(await foo)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '(foo1?.foo2 ?? {}).foo3;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 24,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: 'foo1?.foo2?.foo3;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '((() => foo())() ?? {}).bar;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 28,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(() => foo())()?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: 'const foo = (bar ?? {}).baz;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 13,
+ endColumn: 28,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: 'const foo = bar?.baz;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '(foo.bar ?? {})[baz];',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 21,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: 'foo.bar?.[baz];',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '((foo1 ?? {}).foo2 ?? {}).foo3;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 31,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(foo1 ?? {}).foo2?.foo3;',
+ },
+ ],
+ },
+ {
+ messageId: 'optionalChainSuggest',
+ column: 2,
+ endColumn: 19,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(foo1?.foo2 ?? {}).foo3;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '(foo ?? undefined ?? {}).bar;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(foo ?? undefined)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '(foo() ?? bar ?? {}).baz;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 25,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(foo() ?? bar)?.baz;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '((foo1 ? foo2 : foo3) ?? {}).foo4;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 34,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(foo1 ? foo2 : foo3)?.foo4;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`if (foo) { (foo ?? {}).bar; }`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 12,
+ endColumn: 27,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: noFormat`if (foo) { foo?.bar; }`,
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`if ((foo ?? {}).bar) { foo.bar; }`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 5,
+ endColumn: 20,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: noFormat`if (foo?.bar) { foo.bar; }`,
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`(undefined && foo ?? {}).bar;`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 29,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(undefined && foo)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`(a > b || {}).bar;`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 18,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(a > b)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`(((typeof x) as string) || {}).bar;`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 35,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: noFormat`((typeof x) as string)?.bar;`,
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '(void foo() || {}).bar;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 23,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(void foo())?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '((a ? b : c) || {}).bar;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 24,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(a ? b : c)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`((a instanceof Error) || {}).bar;`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 33,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(a instanceof Error)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`((a << b) || {}).bar;`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 21,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(a << b)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: noFormat`((foo ** 2) || {}).bar;`,
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 23,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(foo ** 2)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '(foo ** 2 || {}).bar;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 21,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(foo ** 2)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '(foo++ || {}).bar;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 18,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(foo++)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
+ {
+ code: '(+foo || {}).bar;',
+ errors: [
+ {
+ messageId: 'optionalChainSuggest',
+ column: 1,
+ endColumn: 17,
+ suggestions: [
+ {
+ messageId: 'optionalChainSuggest',
+ output: '(+foo)?.bar;',
+ },
+ ],
+ },
+ ],
+ },
],
});