# Complete the example · Your first Rell app on Chromia · Learn Chromia > Next, you finish the client so you can exercise the remaining functions. Source: https://chromia.com/learn/book-review/build-client/complete-example/ Your first Rell app on ChromiaLesson 25 of 26 1. [01Your first Rell app on Chromia](https://chromia.com/learn/book-review/introduction/) 2. [02Set up your project](https://chromia.com/learn/book-review/setup/) 3. [03Rell project structure](https://chromia.com/learn/book-review/rell-structure/) Part 1: Define your first entity 1. [04Overview](https://chromia.com/learn/book-review/book-entity/) 2. [05Create your first entity](https://chromia.com/learn/book-review/book-entity/tables/) 3. [06Add your first operation](https://chromia.com/learn/book-review/book-entity/basic-operations/) 4. [07Query every book](https://chromia.com/learn/book-review/book-entity/write-queries/) Part 2: Add a related entity 1. [08Overview](https://chromia.com/learn/book-review/book-review-entity/) 2. [09Define the book review entity](https://chromia.com/learn/book-review/book-review-entity/tables/) 3. [10Add an operation for creating book reviews](https://chromia.com/learn/book-review/book-review-entity/basic-operations/) 4. [11Query all reviews for a book](https://chromia.com/learn/book-review/book-review-entity/write-queries/) Part 3: Checking and validating inputs 1. [12Overview](https://chromia.com/learn/book-review/input-verification/) 2. [13Verify inputs](https://chromia.com/learn/book-review/input-verification/input-verification/) 3. [14Return structured results from queries](https://chromia.com/learn/book-review/input-verification/structure/) Part 4: Signing transactions and filtering queries 1. [15Overview](https://chromia.com/learn/book-review/sign-transaction/) 2. [16Sign a transaction](https://chromia.com/learn/book-review/sign-transaction/sign-transaction/) 3. [17Filter and sort query results](https://chromia.com/learn/book-review/sign-transaction/structure/) Part 5: Blockchain state and transactions explained 1. [18Overview](https://chromia.com/learn/book-review/blockchain-transactions/) 2. [19How blockchain state and transactions work](https://chromia.com/learn/book-review/blockchain-transactions/query-transaction/) 3. [20Walking through an example](https://chromia.com/learn/book-review/blockchain-transactions/example/) Part 6: Create the client 1. [21Overview](https://chromia.com/learn/book-review/build-client/) 2. [22Prerequisites](https://chromia.com/learn/book-review/build-client/prerequisites/) 3. [23Establishing a connection to Chromia](https://chromia.com/learn/book-review/build-client/sign-transaction/) 4. [24Query the blockchain using postchain-client](https://chromia.com/learn/book-review/build-client/query-blockchain/) 5. [25Complete the example](https://chromia.com/learn/book-review/build-client/complete-example/) 1. [26What’s next?](https://chromia.com/learn/book-review/what-next/) [Learn](https://chromia.com/learn/)[Your first Rell app on Chromia](https://chromia.com/learn/book-review/) 25 / 26Part 6: Create the clientBeginner # Complete the example Next, you finish the client so you can exercise the remaining functions. First, declare the last type required to query book reviews: typescript ``` type BookReview = { book: Book; reviewer_name: string; }; ``` Then add the functions that query entities, along with a few helpers that read user input: typescript ``` const rl = readline.createInterface({ input: process.stdin, output: process.stdout, }); function getInput(query: string): Promise { return new Promise((resolve) => { rl.question(query, (answer) => { resolve(answer); }); }); } const getReviewsForBook = async (isbn: string) => { const bookList = await client.query("get_all_reviews_for_book", { isbn: isbn }); console.log("Book review list\n", bookList); }; const getAllTransactions = async () => { const transactions = await client.query("get_transactions", {}); console.dir(transactions, { depth: null, customInspect: true, // This forces Buffer to use hex string output }); }; ``` Finally, here is the complete `main` function. It adds the calls that create books and reviews and retrieve data: typescript ``` async function main() { client = await createClient({ nodeUrlPool: "http://localhost:7740", blockchainRid: blockchainRID, }); console.log("Creating a new book transaction"); await client.signAndSendUniqueTransaction( { name: "create_book", args: ["ISBN1", "Chromia 101", "John Doe"] }, bookKeeperSignatureProvider ); await getInput("Transaction committed!\nPress any key to continue..."); console.log("Let's fetch and view all books currently in the node"); await getAllBooks(); await getInput("Press any key to continue..."); console.log("We can now add a second book"); await client.signAndSendUniqueTransaction( { name: "create_book", args: ["ISBN2", "Rell 101", "Jane Doe"] }, bookKeeperSignatureProvider ); await getInput("Transaction committed, press any key to continue..."); console.log("Let's fetch and view all books currently in the node"); await getAllBooks(); await getInput("Press any key to continue..."); console.log("We can now add two reviews for the book with ISBN = ISBN2"); await client.signAndSendUniqueTransaction( { name: "create_book_review", args: ["ISBN2", "Bob Doe", "This is a great book!", 5], }, bookKeeperSignatureProvider ); await client.signAndSendUniqueTransaction( { name: "create_book_review", args: ["ISBN2", "Charlie Doe", "It was ok!", 3], }, bookKeeperSignatureProvider ); await getInput("Transaction committed, press any key to continue..."); console.log("Let's fetch and view all reviews for ISBN2"); await getReviewsForBook("ISBN2"); await getInput("Press any key to continue..."); console.log("Now let's look at all transactions that have been committed to the blockchain"); await getAllTransactions(); await getInput("Press any key to continue..."); rl.close(); } ``` You now have a working example of a front-end client built with Chromia and `postchain-client`. Written for this site from Chromia’s public course. Code samples are the course’s own. [← Previous**Query the blockchain using postchain-client**](https://chromia.com/learn/book-review/build-client/query-blockchain/)[Next →**What’s next?**](https://chromia.com/learn/book-review/what-next/)