Remove generic isEqual code

Author: schmidt-sebastian

packages/firestore/rollup.config.js

@@ -107,9 +107,9 @@ const es5BuildPlugins = [
   }),
   {
     transform(code) {
-      // Allow Rollup to drop unused classes. 
+      // Allow Rollup to drop unused classes.
       // See https://github.com/rollup/rollup/issues/2807
-      return code.replace(/\/\*\* @class \*\//g, "\/*@__PURE__*\/");
+      return code.replace(/\/\*\* @class \*\//g, '/*@__PURE__*/');
     }
   },
   json(),
@@ -207,9 +207,9 @@ const nodeBuildPlugins = [
   }),
   {
     transform(code) {
-      // Allow Rollup to drop unused classes. 
+      // Allow Rollup to drop unused classes.
       // See https://github.com/rollup/rollup/issues/2807
-      return code.replace(/\/\*\* @class \*\//g, "\/*@__PURE__*\/");
+      return code.replace(/\/\*\* @class \*\//g, '/*@__PURE__*/');
     }
   },
   json(),

packages/firestore/src/model/mutation.ts

@@ -32,7 +32,7 @@ import { DocumentKey } from './document_key';
 import { ObjectValue, ObjectValueBuilder } from './field_value';
 import { FieldPath } from './path';
 import { TransformOperation } from './transform_operation';
-import { arrayEquals, equals } from '../util/misc';
+import { arrayEquals } from '../util/misc';
 
 /**
  * Provides a set of fields that can be used to partially patch a document.
@@ -180,7 +180,10 @@ export class Precondition {
 
   isEqual(other: Precondition): boolean {
     return (
-      equals(this.updateTime, other.updateTime) && this.exists === other.exists
+      this.exists === other.exists &&
+      (this.updateTime
+        ? !!other.updateTime && this.updateTime?.isEqual(other.updateTime)
+        : !other.updateTime)
     );
   }
 }

packages/firestore/src/util/misc.ts

@@ -56,25 +56,6 @@ export function primitiveComparator<T>(left: T, right: T): number {
   return 0;
 }
 
-/** Duck-typed interface for objects that have an isEqual() method. */
-export interface Equatable<T> {
-  isEqual(other: T): boolean;
-}
-
-/** Helper to compare nullable (or undefined-able) objects using isEqual(). */
-export function equals<T>(
-  left: Equatable<T> | null | undefined,
-  right: T | null | undefined
-): boolean {
-  if (left !== null && left !== undefined) {
-    return !!(right && left.isEqual(right));
-  } else {
-    // HACK: Explicitly cast since TypeScript's type narrowing apparently isn't
-    // smart enough.
-    return (left as null | undefined) === right;
-  }
-}
-
 /** Helper to compare arrays using isEqual(). */
 export function arrayEquals<T>(
   left: T[],