Elaborate noIfWithoutElse rule

evansb · Jun 21, 2017 · 4f0236c · 4f0236c
1 parent 7520c69
commit 4f0236c
Show file tree

Hide file tree

Showing 2 changed files with 12 additions and 3 deletions.
diff --git a/packages/toolchain/src/rules/__tests__/noIfWithoutElse.ts b/packages/toolchain/src/rules/__tests__/noIfWithoutElse.ts
@@ -10,7 +10,8 @@ it('detects missing Else case', () => {
   `,
     {
       errorClass: NoIfWithoutElseError,
-      explanation: /Missing.*else.*/
+      explanation: /Missing.*else.*/,
+      elaboration: /2 === 2/
     }
   )
 })
@@ -26,7 +27,8 @@ it('detects missing Else case in if-elseif', () => {
   `,
     {
       errorClass: NoIfWithoutElseError,
-      explanation: /Missing.*else.*/
+      explanation: /Missing.*else.*/,
+      elaboration: /2 === 1/
     }
   )
 })
diff --git a/packages/toolchain/src/rules/noIfWithoutElse.ts b/packages/toolchain/src/rules/noIfWithoutElse.ts
@@ -1,4 +1,5 @@
 import * as es from 'estree'
+import { generate } from 'escodegen'
 import { IError } from '../types/error'
 import { Rule } from '../types/static'
 
@@ -14,7 +15,13 @@ export class NoIfWithoutElseError implements IError {
   }
 
   elaborate() {
-    return 'TODO'
+    return `
+      This "if" block requires corresponding "else" block which will be
+      evaluated when ${generate(this.node.test)} expression evaluates to false.
+
+      Later in the course we will lift this restriction and allow "if" without
+      else.
+    `
   }
 }