fix(core): Remove for-of syntax from core helpers for JSC memory reduction

.changeset/plenty-carrots-confess.md

@@ -0,0 +1,5 @@
+---
+'@urql/core': patch
+---
+
+Remove `for-of` syntax from `@urql/core` helpers for JSC memory reduction.

packages/core/src/client.ts

@@ -649,7 +649,8 @@ export const Client: new (opts: ClientOptions) => Client = function Client(
  } else {
  // If the current result has queued up an operation of the same
  // key, then `stale` refers to it
- for (const operation of queue) {
+ for (let i = 0; i < queue.length; i++) {
+ const operation = queue[i];
  if (operation.key === result.operation.key) {
  dispatched.delete(operation.key);
  break;

packages/core/src/gql.ts

@@ -78,8 +78,9 @@ function gql(parts: string | TemplateStringsArray /* arguments */) {
  }
 
  source.unshift(keyDocument(body));
- for (const document of source) {
- for (const definition of document.definitions) {
+ for (let i = 0; i < source.length; i++) {
+ for (let j = 0; j < source[i].definitions.length; j++) {
+ const definition = source[i].definitions[j];
  if (definition.kind === Kind.FRAGMENT_DEFINITION) {
  const name = definition.name.value;
  const value = stringifyDocument(definition);

packages/core/src/utils/collectTypenames.ts

@@ -5,7 +5,9 @@ interface EntityLike {
 
 const collectTypes = (obj: EntityLike | EntityLike[], types: Set<string>) => {
  if (Array.isArray(obj)) {
- for (const item of obj) collectTypes(item, types);
+ for (let i = 0, l = obj.length; i < l; i++) {
+ collectTypes(obj[i], types);
+ }
  } else if (typeof obj === 'object' && obj !== null) {
  for (const key in obj) {
  if (key === '__typename' && typeof obj[key] === 'string') {

packages/core/src/utils/error.ts

@@ -8,9 +8,9 @@ const generateErrorMessage = (
  let error = '';
  if (networkErr) return `[Network] ${networkErr.message}`;
  if (graphQlErrs) {
- for (const err of graphQlErrs) {
+ for (let i = 0, l = graphQlErrs.length; i < l; i++) {
  if (error) error += '\n';
- error += `[GraphQL] ${err.message}`;
+ error += `[GraphQL] ${graphQlErrs[i].message}`;
  }
  }
  return error;

packages/core/src/utils/formatDocument.ts

@@ -16,8 +16,8 @@ const formatNode = <
 ): FormattedNode<T> => {
  if ('definitions' in node) {
  const definitions: FormattedNode<DefinitionNode>[] = [];
- for (const definition of node.definitions) {
- const newDefinition = formatNode(definition);
+ for (let i = 0, l = node.definitions.length; i < l; i++) {
+ const newDefinition = formatNode(node.definitions[i]);
  definitions.push(newDefinition);
  }
 
@@ -27,7 +27,8 @@ const formatNode = <
  if ('directives' in node && node.directives && node.directives.length) {
  const directives: DirectiveNode[] = [];
  const _directives = {};
- for (const directive of node.directives) {
+ for (let i = 0, l = node.directives.length; i < l; i++) {
+ const directive = node.directives[i];
  let name = directive.name.value;
  if (name[0] !== '_') {
  directives.push(directive);
@@ -43,7 +44,8 @@ const formatNode = <
  const selections: FormattedNode<SelectionNode>[] = [];
  let hasTypename = node.kind === Kind.OPERATION_DEFINITION;
  if (node.selectionSet) {
- for (const selection of node.selectionSet.selections || []) {
+ for (let i = 0, l = node.selectionSet.selections.length; i < l; i++) {
+ const selection = node.selectionSet.selections[i];
  hasTypename =
  hasTypename ||
  (selection.kind === Kind.FIELD &&

packages/core/src/utils/request.ts

@@ -180,7 +180,8 @@ export const createRequest = <
  * @returns the operation's name contained within the document, or `undefined`
  */
 export const getOperationName = (query: DocumentNode): string | undefined => {
- for (const node of query.definitions) {
+ for (let i = 0, l = query.definitions.length; i < l; i++) {
+ const node = query.definitions[i];
  if (node.kind === Kind.OPERATION_DEFINITION) {
  return node.name ? node.name.value : undefined;
  }
@@ -192,7 +193,8 @@ export const getOperationName = (query: DocumentNode): string | undefined => {
  * @returns the operation's type contained within the document, or `undefined`
  */
 export const getOperationType = (query: DocumentNode): string | undefined => {
- for (const node of query.definitions) {
+ for (let i = 0, l = query.definitions.length; i < l; i++) {
+ const node = query.definitions[i];
  if (node.kind === Kind.OPERATION_DEFINITION) {
  return node.operation;
  }

packages/core/src/utils/result.ts

@@ -53,13 +53,18 @@ export const makeResult = (
 
 const deepMerge = (target: any, source: any): any => {
  if (typeof target === 'object' && target != null) {
+ if (Array.isArray(target)) {
+ target = [...target];
+ for (let i = 0, l = source.length; i < l; i++)
+ target[i] = deepMerge(target[i], source[i]);
+ }
  if (
  !target.constructor ||
  target.constructor === Object ||
  Array.isArray(target)
  ) {
- target = Array.isArray(target) ? [...target] : { ...target };
- for (const key of Object.keys(source))
+ target = { ...target };
+ for (const key in source)
  target[key] = deepMerge(target[key], source[key]);
  return target;
  }
@@ -108,7 +113,8 @@ export const mergeResultPatch = (
 
  const withData = { data: prevResult.data };
  if (incremental) {
- for (const patch of incremental) {
+ for (let i = 0, l = incremental.length; i < l; i++) {
+ const patch = incremental[i];
  if (Array.isArray(patch.errors)) {
  errors.push(...(patch.errors as any));
  }

packages/core/src/utils/variables.ts

@@ -12,9 +12,9 @@ const stringify = (x: any, includeFiles: boolean): string => {
  return stringify(x.toJSON(), includeFiles);
  } else if (Array.isArray(x)) {
  let out = '[';
- for (const value of x) {
+ for (let i = 0, l = x.length; i < l; i++) {
  if (out.length > 1) out += ',';
- out += stringify(value, includeFiles) || 'null';
+ out += stringify(x[i], includeFiles) || 'null';
  }
  out += ']';
  return out;
@@ -39,11 +39,11 @@ const stringify = (x: any, includeFiles: boolean): string => {
 
  seen.add(x);
  let out = '{';
- for (const key of keys) {
- const value = stringify(x[key], includeFiles);
+ for (let i = 0, l = keys.length; i < l; i++) {
+ const value = stringify(x[keys[i]], includeFiles);
  if (value) {
  if (out.length > 1) out += ',';
- out += stringify(key, includeFiles) + ':' + value;
+ out += stringify(keys[i], includeFiles) + ':' + value;
  }
  }
 
@@ -62,7 +62,7 @@ const extract = (map: FileMap, path: string, x: any): void => {
  map.set(path, x as File | Blob);
  } else {
  seen.add(x);
- for (const key of Object.keys(x)) extract(map, `${path}.${key}`, x[key]);
+ for (const key in x) extract(map, `${path}.${key}`, x[key]);
  }
 };