Update: Added auto-fix to multiline-ternary

I noticed unfixed warnings from this ESLint rule and wanted to auto-fix them. While it may seem like doing `'\n? '` is opinionated, I did have changed to make this take a new option and either put the `?` on the previous line or next line. This is actually unnecessary because `operator-linebreak` handles it for you.
eslint · Feb 28, 2020 · a00ffc6 · a00ffc6
1 parent 4797fb2
commit a00ffc6
Showing 1 changed file with 63 additions and 9 deletions.
diff --git a/lib/rules/multiline-ternary.js b/lib/rules/multiline-ternary.js
@@ -24,15 +24,18 @@ module.exports = {
 
         schema: [
             {
-                enum: ["always", "always-multiline", "never"]
-            }
+                enum: ["always", "always-multiline", "never"],
+            },
         ],
+
         messages: {
             expectedTestCons: "Expected newline between test and consequent of ternary expression.",
             expectedConsAlt: "Expected newline between consequent and alternate of ternary expression.",
             unexpectedTestCons: "Unexpected newline between test and consequent of ternary expression.",
             unexpectedConsAlt: "Unexpected newline between consequent and alternate of ternary expression."
-        }
+        },
+
+        fixable: 'code',
     },
 
     create(context) {
@@ -52,10 +55,61 @@ module.exports = {
          * @returns {void}
          * @private
          */
-        function reportError(node, parentNode, expected) {
+        function reportSingleLineError(node, parentNode, expected) {
+            context.report({
+                node,
+                messageId: `${expected ? "expected" : "unexpected"}${node === parentNode.test ? "TestCons" : "ConsAlt"}`,
+                fix: fixer => ([
+                    !astUtils.isTokenOnSameLine(parentNode.test, parentNode.consequent) &&
+                    fixer.replaceTextRange(
+                        [
+                            parentNode.test.range[1],
+                            parentNode.consequent.range[0],
+                        ],
+                        ' ? ',
+                    ),
+                    !astUtils.isTokenOnSameLine(parentNode.consequent, parentNode.alternate) &&
+                    fixer.replaceTextRange(
+                        [
+                            parentNode.consequent.range[1],
+                            parentNode.alternate.range[0],
+                        ],
+                        ' : ',
+                    ),
+                ]),
+            });
+        }
+
+        /**
+         * Tests whether node is preceded by supplied tokens
+         * @param {ASTNode} node node to check
+         * @param {ASTNode} parentNode parent of node to report
+         * @param {boolean} expected whether newline was expected or not
+         * @returns {void}
+         * @private
+         */
+        function reportMultilineError(node, parentNode, expected) {
             context.report({
                 node,
-                messageId: `${expected ? "expected" : "unexpected"}${node === parentNode.test ? "TestCons" : "ConsAlt"}`
+                messageId: `${expected ? "expected" : "unexpected"}${node === parentNode.test ? "TestCons" : "ConsAlt"}`,
+                fix: fixer => ([
+                    astUtils.isTokenOnSameLine(parentNode.test, parentNode.consequent) &&
+                    fixer.replaceTextRange(
+                        [
+                            parentNode.test.range[1],
+                            parentNode.consequent.range[0],
+                        ],
+                        '\n? ',
+                    ),
+                    astUtils.isTokenOnSameLine(parentNode.consequent, parentNode.alternate) &&
+                    fixer.replaceTextRange(
+                        [
+                            parentNode.consequent.range[1],
+                            parentNode.alternate.range[0],
+                        ],
+                        '\n: ',
+                    ),
+                ]),
             });
         }
 
@@ -70,23 +124,23 @@ module.exports = {
 
                 if (!multiline) {
                     if (!areTestAndConsequentOnSameLine) {
-                        reportError(node.test, node, false);
+                        reportSingleLineError(node.test, node, false);
                     }
 
                     if (!areConsequentAndAlternateOnSameLine) {
-                        reportError(node.consequent, node, false);
+                        reportSingleLineError(node.consequent, node, false);
                     }
                 } else {
                     if (allowSingleLine && node.loc.start.line === node.loc.end.line) {
                         return;
                     }
 
                     if (areTestAndConsequentOnSameLine) {
-                        reportError(node.test, node, true);
+                        reportMultilineError(node.test, node, true);
                     }
 
                     if (areConsequentAndAlternateOnSameLine) {
-                        reportError(node.consequent, node, true);
+                        reportMultilineError(node.consequent, node, true);
                     }
                 }
             }