Cloud Firestore Node.js Client Library

The Firestore Pipelines API (currently @beta) provides functional expressions for advanced querying and data manipulation.

Array Operations:

• arrayLength(array): Returns the length of an array.
• arraySum(array): Returns the sum of elements in an array.
• arrayMaximum(array) / arrayMinimum(array): Returns the max/min value.
• arrayReverse(array): Reverses the array.
• arrayMaximumN(array, n): Returns the top n maximum values.

Aggregate & Ordering Operations:

• average(expression): Calculates the average of a field or expression.
• ascending(expr): Defines ascending order for a query.
• byteLength(expr): Returns the byte length of a string or expression.
• charLength(expr): Returns the character length of a string.
• ceil(expr): Returns the ceiling of a numeric value.

Boolean Expressions:

• BooleanExpression objects support logical operations like .not() and conditional logic via .conditional(thenExpr, elseExpr) and .ifError(catchValue).

The library provides a set of @beta expression functions for complex data manipulation and filtering within queries. These functions typically return a BooleanExpression (for filtering) or a FunctionExpression (for transformation).

String Operations:

• startsWith(fieldName, prefix): Returns a BooleanExpression checking if a field starts with a prefix.
• stringContains(fieldName, substring): Returns a BooleanExpression checking if a field contains a substring.
• stringConcat(fieldName, ...strings): Returns a FunctionExpression to concatenate strings.
• split(fieldName, delimiter): Returns a FunctionExpression to split a string.
• reverse(expression): Returns a FunctionExpression to reverse a string.

Regex Operations:

• regexMatch(fieldName, pattern): Returns a BooleanExpression for regex matching.
• regexContains(fieldName, pattern): Returns a BooleanExpression for regex containment.
• regexFind(fieldName, pattern): Returns a FunctionExpression to find matches.
• regexFindAll(fieldName, pattern): Returns a FunctionExpression to find all matches.

Math and Numeric Operations:

• round(fieldName, decimalPlaces): Returns a FunctionExpression to round a number.
• sqrt(expression): Returns a FunctionExpression for square root.

Other Operations:

• rand(): Returns a FunctionExpression for random values.
• rtrim(fieldName, valueToTrim): Returns a FunctionExpression to trim characters from the right.

The @beta Firestore Pipelines API provides a set of functions to build complex expressions for advanced querying and data manipulation. These functions are used to construct Expression objects.

Mathematical & Logical Expressions:

• constant(value): Creates a Constant expression from a value (number, string, boolean, null, Date, etc.).
• concat(...others): Concatenates multiple expressions.
• conditional(condition, thenExpr, elseExpr): Returns a conditional expression.
• divide(dividend, divisor): Performs division between expressions.

Aggregation Functions:

• count(expression | fieldName | 'all'): Counts documents.
• countDistinct(expr | string): Counts distinct values.
• countIf(booleanExpr): Counts documents matching a condition.

Vector & Similarity Search:

• cosineDistance(fieldName | vectorExpression, vector | vectorExpression): Calculates cosine distance for vector similarity searches.

Field & Identity Expressions:

• collectionId(fieldName | expression): Returns the ID of the collection.
• documentId(documentPath | expression): Returns the ID of a document.
• currentTimestamp(): Returns the current server timestamp.

This guide demonstrates how to initialize a Firestore client and perform basic Create, Read, Update, and Delete (CRUD) operations on a document.

const {Firestore} = require('@google-cloud/firestore');

// Create a new client
const firestore = new Firestore();

async function quickstart() {
  // Obtain a document reference.
  const document = firestore.doc('posts/intro-to-firestore');

  // Enter new data into the document.
  await document.set({
    title: 'Welcome to Firestore',
    body: 'Hello World',
  });
  console.log('Entered new data into the document');

  // Update an existing document.
  await document.update({
    body: 'My first Firestore app',
  });
  console.log('Updated an existing document');

  // Read the document.
  const doc = await document.get();
  console.log('Read the document');

  // Delete the document.
  await document.delete();
  console.log('Deleted the document');
}
quickstart();