Taking into account Apollo fragment interpolation

src/index.js

@@ -257,12 +257,24 @@ function replaceExpressions(node, context, env) {
 
   node.quasis.forEach((element, i) => {
     const chunk = element.value.cooked;
+    const value = node.expressions[i];
 
     chunks.push(chunk);
 
-    if (!element.tail) {
-      const value = node.expressions[i];
+    if (!env || env === 'apollo') {
+      // In Apollo, interpolation is only valid outside top-level structures like `query` or `mutation`.
+      // We'll check to make sure there's an equivalent set of opening and closing brackets, otherwise
+      // we're attempting to do an invalid interpolation.
+      if ((chunk.split('{').length - 1) !== (chunk.split('}').length - 1)) {
+        context.report({
+          node: value,
+          message: 'Invalid interpolation - fragment interpolation must occur outside of the brackets.',
+        });
+        throw new Error('Invalid interpolation');
+      }
+    }
 
+    if (!element.tail) {
       // Preserve location of errors by replacing with exactly the same length
       const nameLength = value.end - value.start;
 
@@ -282,6 +294,10 @@ function replaceExpressions(node, context, env) {
         // Ellipsis cancels out extra characters
         const placeholder = strWithLen(nameLength);
         chunks.push('...' + placeholder);
+      } else if (!env || env === 'apollo') {
+        // In Apollo, fragment interpolation is only valid outside of brackets
+        // Since we don't know what we'd interpolate here (that occurs at runtime),
+        // we're not going to do anything with this interpolation.
       } else {
         // Invalid interpolation
         context.report({

test/makeRule.js

@@ -45,11 +45,15 @@ const parserOptions = {
         options,
         parserOptions,
         code: 'const x = gql.segmented`height: 12px;`'
-      }
+      },
+      {
+        options,
+        parserOptions,
+        code: 'const x = gql`{ number } ${x}`',
+      },
     ],
 
     invalid: [
-
       {
         options,
         parserOptions,
@@ -73,8 +77,10 @@ const parserOptions = {
         parserOptions,
         code: 'const x = gql`{ ${x} }`',
         errors: [{
-          message: 'Invalid interpolation - not a valid fragment or variable.',
-          type: 'Identifier'
+          message: 'Invalid interpolation - fragment interpolation must occur outside of the brackets.',
+          type: 'Identifier',
+          line: 1,
+          column: 19
         }]
       },
     ]
@@ -120,13 +126,50 @@ const parserOptions = {
         code: 'const x = myGraphQLTag`{ ${x} }`',
         errors: [{
           type: 'Identifier',
-          message: 'Invalid interpolation - not a valid fragment or variable.'
+          message: 'Invalid interpolation - fragment interpolation must occur outside of the brackets.'
         }]
       },
     ]
   });
 }
 
+{
+  const options = [
+    { schemaJson, env: 'apollo' },
+  ];
+
+  ruleTester.run('apollo', rule, {
+    valid: [
+      {
+        options,
+        parserOptions,
+        code: 'const x = gql`{ number } ${x}`',
+      },
+    ],
+
+    invalid: [
+      {
+        options,
+        parserOptions,
+        code: 'const x = gql`query { ${x} }`',
+        errors: [{
+          message: 'Invalid interpolation - fragment interpolation must occur outside of the brackets.',
+          type: 'Identifier'
+        }]
+      },
+      {
+        options,
+        parserOptions,
+        code: 'const x = gql`query }{ ${x}`',
+        errors: [{
+          message: 'Syntax Error GraphQL (1:7) Expected {, found }',
+          type: 'TaggedTemplateExpression'
+        }]
+      }
+    ],
+  })
+}
+
 {
   const options = [
     { schemaJson, env: 'lokka' },
@@ -263,6 +306,29 @@ const parserOptions = {
           column: 19
         }]
       },
+      {
+        options,
+        parserOptions,
+        code: `
+          client.query(gql\`
+            {
+              allFilms {
+                films {
+                  \${filmInfo}
+                }
+              }
+            }
+          \`).then(result => {
+            console.log(result.allFilms.films);
+          });
+        `,
+        errors: [{
+          message: 'Invalid interpolation - not a valid fragment or variable.',
+          type: 'Identifier',
+          line: 6,
+          column: 21
+        }]
+      },
     ]
   });
 }