Add strictIteration option

Author: markerikson

src/core/immerClass.ts

@@ -31,20 +31,24 @@ interface ProducersFns {
 	produceWithPatches: IProduceWithPatches
 }
 
-export type StrictMode = boolean | "class_only";
+export type StrictMode = boolean | "class_only"
 
 export class Immer implements ProducersFns {
 	autoFreeze_: boolean = true
 	useStrictShallowCopy_: StrictMode = false
+	useStrictIteration_: boolean = false
 
 	constructor(config?: {
 		autoFreeze?: boolean
 		useStrictShallowCopy?: StrictMode
+		useStrictIteration?: boolean
 	}) {
 		if (typeof config?.autoFreeze === "boolean")
 			this.setAutoFreeze(config!.autoFreeze)
 		if (typeof config?.useStrictShallowCopy === "boolean")
 			this.setUseStrictShallowCopy(config!.useStrictShallowCopy)
+		if (typeof config?.useStrictIteration === "boolean")
+			this.setUseStrictIteration(config!.useStrictIteration)
 	}
 
 	/**
@@ -172,6 +176,20 @@ export class Immer implements ProducersFns {
 		this.useStrictShallowCopy_ = value
 	}
 
+	/**
+	 * Pass false to use faster iteration that skips non-enumerable properties
+	 * but still handles symbols for compatibility.
+	 *
+	 * By default, strict iteration is enabled (includes all own properties).
+	 */
+	setUseStrictIteration(value: boolean) {
+		this.useStrictIteration_ = value
+	}
+
+	shouldUseStrictIteration(obj: any): boolean {
+		return this.useStrictIteration_
+	}
+
 	applyPatches<T extends Objectish>(base: T, patches: readonly Patch[]): T {
 		// If a patch replaces the entire state, take that replacement as base
 		// before applying patches

src/immer.ts

@@ -71,6 +71,16 @@ export const setUseStrictShallowCopy = /* @__PURE__ */ immer.setUseStrictShallow
 	immer
 )
 
+/**
+ * Pass false to use ultra-fast iteration that only processes enumerable string properties.
+ * This skips symbols and non-enumerable properties for maximum performance.
+ *
+ * By default, strict iteration is enabled (includes all own properties).
+ */
+export const setUseStrictIteration = /* @__PURE__ */ immer.setUseStrictIteration.bind(
+	immer
+)
+
 /**
  * Apply an array of Immer patches to the first argument.
  *