feat: add isType expression

google-cloud-firestore/src/main/java/com/google/cloud/firestore/pipeline/expressions/Expression.java

@@ -3130,6 +3130,34 @@ public static Expression type(String fieldName) {
     return type(field(fieldName));
   }
 
+  /**
+   * Creates an expression that checks if the result of this expression is of the given type.
+   *
+   * @param expr The expression to check the type of.
+   * @param type The type to check for.
+   * @return A new {@link BooleanExpression} that evaluates to true if the expression's result is of
+   *     the given type, false otherwise.
+   */
+  @BetaApi
+  public static BooleanExpression isType(Expression expr, Type type) {
+    return new BooleanFunctionExpression(
+        "is_type", ImmutableList.of(expr, constant(type.name().toLowerCase())));
+  }
+
+  /**
+   * Creates an expression that checks if the result of this expression is of the given type.
+   *
+   * @param fieldName The name of the field to check the type of.
+   * @param type The type to check for.
+   * @return A new {@link BooleanExpression} that evaluates to true if the expression's result is of
+   *     the given type, false otherwise.
+   */
+  @BetaApi
+  public static BooleanExpression isType(String fieldName, Type type) {
+    return new BooleanFunctionExpression(
+        "is_type", ImmutableList.of(field(fieldName), constant(type.name().toLowerCase())));
+  }
+
   // Numeric Operations
   /**
    * Creates an expression that rounds {@code numericExpr} to nearest integer.
@@ -4796,4 +4824,16 @@ public final Expression collectionId() {
   public final Expression type() {
     return type(this);
   }
+
+  /**
+   * Creates an expression that checks if the result of this expression is of the given type.
+   *
+   * @param type The type to check for.
+   * @return A new {@link BooleanExpression} that evaluates to true if the expression's result is of
+   *     the given type, false otherwise.
+   */
+  @BetaApi
+  public final Expression isType(Type type) {
+    return isType(this, type);
+  }
 }

google-cloud-firestore/src/main/java/com/google/cloud/firestore/pipeline/expressions/Type.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2026 Google LLC.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.cloud.firestore.pipeline.expressions;
+
+import com.google.api.core.BetaApi;
+
+/** An enumeration of the different types generated by the Firestore backend. */
+@BetaApi
+public enum Type {
+  NULL,
+  ARRAY,
+  BOOLEAN,
+  BYTES,
+  TIMESTAMP,
+  GEO_POINT,
+  NUMBER,
+  INT32,
+  INT64,
+  FLOAT64,
+  DECIMAL128,
+  MAP,
+  REFERENCE,
+  STRING,
+  VECTOR,
+  MAX_KEY,
+  MIN_KEY,
+  OBJECT_ID,
+  REGEX,
+  REQUEST_TIMESTAMP,
+}

google-cloud-firestore/src/test/java/com/google/cloud/firestore/it/ITPipelineTest.java

@@ -90,6 +90,7 @@
 import com.google.cloud.firestore.pipeline.expressions.AggregateFunction;
 import com.google.cloud.firestore.pipeline.expressions.Expression;
 import com.google.cloud.firestore.pipeline.expressions.Field;
+import com.google.cloud.firestore.pipeline.expressions.Type;
 import com.google.cloud.firestore.pipeline.stages.Aggregate;
 import com.google.cloud.firestore.pipeline.stages.AggregateHints;
 import com.google.cloud.firestore.pipeline.stages.AggregateOptions;
@@ -2633,6 +2634,89 @@ public void testType() throws Exception {
                 "vector"));
   }
 
+  @Test
+  public void testIsType() throws Exception {
+    List<PipelineResult> results =
+        firestore
+            .pipeline()
+            .collection(collection.getPath())
+            .replaceWith(
+                Expression.map(
+                    map(
+                        "int",
+                        1,
+                        "float",
+                        1.1,
+                        "str",
+                        "a string",
+                        "bool",
+                        true,
+                        "null",
+                        null,
+                        "geoPoint",
+                        new GeoPoint(0.1, 0.2),
+                        "timestamp",
+                        Timestamp.ofTimeSecondsAndNanos(123456, 0),
+                        "bytes",
+                        com.google.cloud.firestore.Blob.fromBytes(new byte[] {1, 2, 3}),
+                        "docRef",
+                        collection.document("bar"),
+                        "vector",
+                        vector(new double[] {1.0, 2.0, 3.0}),
+                        "map",
+                        Expression.map(map("numberK", 1, "stringK", "a string")),
+                        "array",
+                        array(1, 2, true))))
+            .select(
+                Expression.isType("int", Type.INT64).as("isInt64"),
+                Expression.isType("int", Type.NUMBER).as("isInt64IsNumber"),
+                Expression.isType("int", Type.DECIMAL128).as("isInt64IsDecimal128"),
+                Expression.isType("float", Type.FLOAT64).as("isFloat64"),
+                Expression.isType("float", Type.NUMBER).as("isFloat64IsNumber"),
+                Expression.isType("float", Type.DECIMAL128).as("isFloat64IsDecimal128"),
+                Expression.isType("str", Type.STRING).as("isStr"),
+                Expression.isType("str", Type.INT64).as("isStrNum"),
+                Expression.isType("int", Type.STRING).as("isNumStr"),
+                Expression.isType("bool", Type.BOOLEAN).as("isBool"),
+                Expression.isType("null", Type.NULL).as("isNull"),
+                Expression.isType("geoPoint", Type.GEO_POINT).as("isGeoPoint"),
+                Expression.isType("timestamp", Type.TIMESTAMP).as("isTimestamp"),
+                Expression.isType("bytes", Type.BYTES).as("isBytes"),
+                Expression.isType("docRef", Type.REFERENCE).as("isDocRef"),
+                Expression.isType("vector", Type.VECTOR).as("isVector"),
+                Expression.isType("map", Type.MAP).as("isMap"),
+                Expression.isType("array", Type.ARRAY).as("isArray"),
+                Expression.isType(constant(1), Type.INT64).as("exprIsInt64"),
+                field("int").isType(Type.INT64).as("staticIsInt64"))
+            .limit(1)
+            .execute()
+            .get()
+            .getResults();
+    assertThat(data(results))
+        .containsExactly(
+            map(
+                "isInt64", true,
+                "isInt64IsNumber", true,
+                "isInt64IsDecimal128", false,
+                "isFloat64", true,
+                "isFloat64IsNumber", true,
+                "isFloat64IsDecimal128", false,
+                "isStr", true,
+                "isStrNum", false,
+                "isNumStr", false,
+                "isBool", true,
+                "isNull", true,
+                "isGeoPoint", true,
+                "isTimestamp", true,
+                "isBytes", true,
+                "isDocRef", true,
+                "isVector", true,
+                "isMap", true,
+                "isArray", true,
+                "exprIsInt64", true,
+                "staticIsInt64", true));
+  }
+
   @Test
   public void testExplainWithError() {
     assumeFalse(

samples/preview-snippets/src/main/java/com/example/firestore/PipelineSnippets.java

@@ -31,6 +31,7 @@
 import com.google.cloud.firestore.PlanSummary;
 import com.google.cloud.firestore.Query;
 import com.google.cloud.firestore.QuerySnapshot;
+import com.google.cloud.firestore.pipeline.expressions.Type;
 import com.google.cloud.firestore.pipeline.stages.Aggregate;
 import com.google.cloud.firestore.pipeline.stages.FindNearest;
 import com.google.cloud.firestore.pipeline.stages.FindNearestOptions;
@@ -1551,6 +1552,19 @@ void vectorLengthFunction() throws ExecutionException, InterruptedException {
     System.out.println(result.getResults());
   }
 
+  void isTypeFunction() throws ExecutionException, InterruptedException {
+    // [START is_type]
+    Pipeline.Snapshot result =
+        firestore
+            .pipeline()
+            .collection("books")
+            .select(field("rating").isType(Type.INT64).as("isRatingInt64"))
+            .execute()
+            .get();
+    // [END is_type]
+    System.out.println(result.getResults());
+  }
+
   // https://cloud.google.com/firestore/docs/pipeline/getting-started/stages-expressions
   void stagesExpressionsExample() throws ExecutionException, InterruptedException {
     // [START stages_expressions_example]