ESLint: enable some of the rules previously blocked by TS conversion (#…

…3277)

.eslintrc.yml

@@ -473,7 +473,8 @@ overrides:
       '@typescript-eslint/ban-tslint-comment': error
       '@typescript-eslint/ban-types': off # TODO temporarily disabled
       '@typescript-eslint/class-literal-property-style': off # TODO enable after TS conversion
-      '@typescript-eslint/consistent-indexed-object-style': off # TODO enable after TS conversion
+      '@typescript-eslint/consistent-indexed-object-style':
+        [error, index-signature]
       '@typescript-eslint/consistent-type-assertions': off # TODO temporarily disable
       '@typescript-eslint/consistent-type-definitions': error
       '@typescript-eslint/consistent-type-imports': error
@@ -507,7 +508,7 @@ overrides:
       '@typescript-eslint/no-require-imports': error
       '@typescript-eslint/no-this-alias': error
       '@typescript-eslint/no-type-alias': off # TODO consider
-      '@typescript-eslint/no-unnecessary-boolean-literal-compare': off # FIXME requires on strictNullChecks
+      '@typescript-eslint/no-unnecessary-boolean-literal-compare': error
       '@typescript-eslint/no-unnecessary-condition': off # TODO temporary disable
       '@typescript-eslint/no-unnecessary-qualifier': error
       '@typescript-eslint/no-unnecessary-type-arguments': error
@@ -522,9 +523,9 @@ overrides:
       '@typescript-eslint/non-nullable-type-assertion-style': off #TODO temporarily disabled
       '@typescript-eslint/prefer-as-const': error
       '@typescript-eslint/prefer-enum-initializers': error
-      '@typescript-eslint/prefer-for-of': off # TODO switch to error after TS migration
+      '@typescript-eslint/prefer-for-of': error
       '@typescript-eslint/prefer-function-type': error
-      '@typescript-eslint/prefer-includes': off # TODO switch to error after IE11 drop
+      '@typescript-eslint/prefer-includes': error
       '@typescript-eslint/prefer-literal-enum-member': error
       '@typescript-eslint/prefer-namespace-keyword': error
       '@typescript-eslint/prefer-nullish-coalescing': error
@@ -534,7 +535,7 @@ overrides:
       '@typescript-eslint/prefer-reduce-type-parameter': error
       '@typescript-eslint/prefer-regexp-exec': off
       '@typescript-eslint/prefer-return-this-type': error
-      '@typescript-eslint/prefer-string-starts-ends-with': off # TODO switch to error after IE11 drop
+      '@typescript-eslint/prefer-string-starts-ends-with': error
       '@typescript-eslint/prefer-ts-expect-error': error
       '@typescript-eslint/promise-function-async': off
       '@typescript-eslint/require-array-sort-compare': error

src/language/blockString.ts

@@ -35,8 +35,8 @@ export function dedentBlockStringValue(rawString: string): string {
 }
 
 function isBlank(str: string): boolean {
-  for (let i = 0; i < str.length; ++i) {
-    if (str[i] !== ' ' && str[i] !== '\t') {
+  for (const char of str) {
+    if (char !== ' ' && char !== '\t') {
       return false;
     }
   }
@@ -96,9 +96,9 @@ export function printBlockString(
   preferMultipleLines: boolean = false,
 ): string {
   const isSingleLine = !value.includes('\n');
-  const hasLeadingSpace = value[0] === ' ' || value[0] === '\t';
-  const hasTrailingQuote = value[value.length - 1] === '"';
-  const hasTrailingSlash = value[value.length - 1] === '\\';
+  const hasLeadingSpace = value.startsWith(' ') || value.startsWith('\t');
+  const hasTrailingQuote = value.endsWith('"');
+  const hasTrailingSlash = value.endsWith('\\');
   const printAsMultipleLines =
     !isSingleLine ||
     hasTrailingQuote ||

src/language/visitor.ts

@@ -211,20 +211,25 @@ export function visit(
       node = parent;
       parent = ancestors.pop();
       if (isEdited) {
-        node = inArray
-          ? node.slice()
-          : Object.defineProperties({}, Object.getOwnPropertyDescriptors(node));
-        let editOffset = 0;
-        for (let ii = 0; ii < edits.length; ii++) {
-          let editKey: any = edits[ii][0];
-          const editValue = edits[ii][1];
-          if (inArray) {
-            editKey -= editOffset;
+        if (inArray) {
+          node = node.slice();
+
+          let editOffset = 0;
+          for (const [editKey, editValue] of edits) {
+            const arrayKey = editKey - editOffset;
+            if (editValue === null) {
+              node.splice(arrayKey, 1);
+              editOffset++;
+            } else {
+              node[arrayKey] = editValue;
+            }
           }
-          if (inArray && editValue === null) {
-            node.splice(editKey, 1);
-            editOffset++;
-          } else {
+        } else {
+          node = Object.defineProperties(
+            {},
+            Object.getOwnPropertyDescriptors(node),
+          );
+          for (const [editKey, editValue] of edits) {
             node[editKey] = editValue;
           }
         }

src/utilities/assertValidName.ts

@@ -20,7 +20,7 @@ export function assertValidName(name: string): string {
  */
 export function isValidNameError(name: string): GraphQLError | undefined {
   devAssert(typeof name === 'string', 'Expected name to be a string.');
-  if (name.length > 1 && name[0] === '_' && name[1] === '_') {
+  if (name.startsWith('__')) {
     return new GraphQLError(
       `Name "${name}" must not begin with "__", which is reserved by GraphQL introspection.`,
     );

src/utilities/stripIgnoredCharacters.ts

@@ -112,9 +112,8 @@ function dedentBlockString(blockStr: string): string {
     body = '\n' + body;
   }
 
-  const lastChar = body[body.length - 1];
-  const hasTrailingQuote = lastChar === '"' && body.slice(-4) !== '\\"""';
-  if (hasTrailingQuote || lastChar === '\\') {
+  const hasTrailingQuote = body.endsWith('"') && !body.endsWith('\\"""');
+  if (hasTrailingQuote || body.endsWith('\\')) {
     body += '\n';
   }
 

src/utilities/typedQueryDocumentNode.ts

@@ -3,8 +3,8 @@ import type { DocumentNode, ExecutableDefinitionNode } from '../language/ast';
  * Wrapper type that contains DocumentNode and types that can be deduced from it.
  */
 export interface TypedQueryDocumentNode<
-  TResponseData = Record<string, any>,
-  TRequestVariables = Record<string, any>,
+  TResponseData = { [key: string]: any },
+  TRequestVariables = { [key: string]: any },
 > extends DocumentNode {
   readonly definitions: ReadonlyArray<ExecutableDefinitionNode>;
   // FIXME: remove once TS implements proper way to enforce nominal typing

src/validation/rules/OverlappingFieldsCanBeMergedRule.ts

@@ -238,11 +238,12 @@ function collectConflictsBetweenFieldsAndFragment(
     return;
   }
 
-  const [fieldMap2, fragmentNames2] = getReferencedFieldsAndFragmentNames(
-    context,
-    cachedFieldsAndFragmentNames,
-    fragment,
-  );
+  const [fieldMap2, referencedFragmentNames] =
+    getReferencedFieldsAndFragmentNames(
+      context,
+      cachedFieldsAndFragmentNames,
+      fragment,
+    );
 
   // Do not compare a fragment's fieldMap to itself.
   if (fieldMap === fieldMap2) {
@@ -263,15 +264,15 @@ function collectConflictsBetweenFieldsAndFragment(
 
   // (E) Then collect any conflicts between the provided collection of fields
   // and any fragment names found in the given fragment.
-  for (let i = 0; i < fragmentNames2.length; i++) {
+  for (const referencedFragmentName of referencedFragmentNames) {
     collectConflictsBetweenFieldsAndFragment(
       context,
       conflicts,
       cachedFieldsAndFragmentNames,
       comparedFragmentPairs,
       areMutuallyExclusive,
       fieldMap,
-      fragmentNames2[i],
+      referencedFragmentName,
     );
   }
 }
@@ -310,16 +311,18 @@ function collectConflictsBetweenFragments(
     return;
   }
 
-  const [fieldMap1, fragmentNames1] = getReferencedFieldsAndFragmentNames(
-    context,
-    cachedFieldsAndFragmentNames,
-    fragment1,
-  );
-  const [fieldMap2, fragmentNames2] = getReferencedFieldsAndFragmentNames(
-    context,
-    cachedFieldsAndFragmentNames,
-    fragment2,
-  );
+  const [fieldMap1, referencedFragmentNames1] =
+    getReferencedFieldsAndFragmentNames(
+      context,
+      cachedFieldsAndFragmentNames,
+      fragment1,
+    );
+  const [fieldMap2, referencedFragmentNames2] =
+    getReferencedFieldsAndFragmentNames(
+      context,
+      cachedFieldsAndFragmentNames,
+      fragment2,
+    );
 
   // (F) First, collect all conflicts between these two collections of fields
   // (not including any nested fragments).
@@ -335,28 +338,28 @@ function collectConflictsBetweenFragments(
 
   // (G) Then collect conflicts between the first fragment and any nested
   // fragments spread in the second fragment.
-  for (let j = 0; j < fragmentNames2.length; j++) {
+  for (const referencedFragmentName2 of referencedFragmentNames2) {
     collectConflictsBetweenFragments(
       context,
       conflicts,
       cachedFieldsAndFragmentNames,
       comparedFragmentPairs,
       areMutuallyExclusive,
       fragmentName1,
-      fragmentNames2[j],
+      referencedFragmentName2,
     );
   }
 
   // (G) Then collect conflicts between the second fragment and any nested
   // fragments spread in the first fragment.
-  for (let i = 0; i < fragmentNames1.length; i++) {
+  for (const referencedFragmentName1 of referencedFragmentNames1) {
     collectConflictsBetweenFragments(
       context,
       conflicts,
       cachedFieldsAndFragmentNames,
       comparedFragmentPairs,
       areMutuallyExclusive,
-      fragmentNames1[i],
+      referencedFragmentName1,
       fragmentName2,
     );
   }
@@ -403,49 +406,45 @@ function findConflictsBetweenSubSelectionSets(
 
   // (I) Then collect conflicts between the first collection of fields and
   // those referenced by each fragment name associated with the second.
-  if (fragmentNames2.length !== 0) {
-    for (let j = 0; j < fragmentNames2.length; j++) {
-      collectConflictsBetweenFieldsAndFragment(
-        context,
-        conflicts,
-        cachedFieldsAndFragmentNames,
-        comparedFragmentPairs,
-        areMutuallyExclusive,
-        fieldMap1,
-        fragmentNames2[j],
-      );
-    }
+  for (const fragmentName2 of fragmentNames2) {
+    collectConflictsBetweenFieldsAndFragment(
+      context,
+      conflicts,
+      cachedFieldsAndFragmentNames,
+      comparedFragmentPairs,
+      areMutuallyExclusive,
+      fieldMap1,
+      fragmentName2,
+    );
   }
 
   // (I) Then collect conflicts between the second collection of fields and
   // those referenced by each fragment name associated with the first.
-  if (fragmentNames1.length !== 0) {
-    for (let i = 0; i < fragmentNames1.length; i++) {
-      collectConflictsBetweenFieldsAndFragment(
-        context,
-        conflicts,
-        cachedFieldsAndFragmentNames,
-        comparedFragmentPairs,
-        areMutuallyExclusive,
-        fieldMap2,
-        fragmentNames1[i],
-      );
-    }
+  for (const fragmentName1 of fragmentNames1) {
+    collectConflictsBetweenFieldsAndFragment(
+      context,
+      conflicts,
+      cachedFieldsAndFragmentNames,
+      comparedFragmentPairs,
+      areMutuallyExclusive,
+      fieldMap2,
+      fragmentName1,
+    );
   }
 
   // (J) Also collect conflicts between any fragment names by the first and
   // fragment names by the second. This compares each item in the first set of
   // names to each item in the second set of names.
-  for (let i = 0; i < fragmentNames1.length; i++) {
-    for (let j = 0; j < fragmentNames2.length; j++) {
+  for (const fragmentName1 of fragmentNames1) {
+    for (const fragmentName2 of fragmentNames2) {
       collectConflictsBetweenFragments(
         context,
         conflicts,
         cachedFieldsAndFragmentNames,
         comparedFragmentPairs,
         areMutuallyExclusive,
-        fragmentNames1[i],
-        fragmentNames2[j],
+        fragmentName1,
+        fragmentName2,
       );
     }
   }
@@ -511,16 +510,16 @@ function collectConflictsBetween(
   for (const [responseName, fields1] of Object.entries(fieldMap1)) {
     const fields2 = fieldMap2[responseName];
     if (fields2) {
-      for (let i = 0; i < fields1.length; i++) {
-        for (let j = 0; j < fields2.length; j++) {
+      for (const field1 of fields1) {
+        for (const field2 of fields2) {
           const conflict = findConflict(
             context,
             cachedFieldsAndFragmentNames,
             comparedFragmentPairs,
             parentFieldsAreMutuallyExclusive,
             responseName,
-            fields1[i],
-            fields2[j],
+            field1,
+            field2,
           );
           if (conflict) {
             conflicts.push(conflict);

src/validation/rules/SingleFieldSubscriptionsRule.ts

@@ -61,7 +61,7 @@ export function SingleFieldSubscriptionsRule(
           for (const fieldNodes of fields.values()) {
             const field = fieldNodes[0];
             const fieldName = field.name.value;
-            if (fieldName[0] === '_' && fieldName[1] === '_') {
+            if (fieldName.startsWith('__')) {
               context.reportError(
                 new GraphQLError(
                   operationName != null