Weave with TypeScript Quickstart Guide

You can use W&B Weave with Typescript to:

• Log and debug language model inputs, outputs, and traces
• Build rigorous, apples-to-apples evaluations for language model use cases
• Organize all the information generated across the LLM workflow, from experimentation to evaluations to production

For more information, see the Weave documentation.

Function tracking

To use Weave in your Typescript code, initialize a new Weave project and add the weave.op wrapper to the functions you want to track.

After adding weave.op and calling the function, visit the W&B dashboard to see it tracked within your project.

We automatically track your code - check the code tab in the UI!

async function initializeWeaveProject() {
    const PROJECT = 'weave-examples';
    await weave.init(PROJECT);
}

const stripUserInput = weave.op(function stripUserInput(userInput: string): string {
    return userInput.trim();
});

The following example shows how basic function tracking works.

async function demonstrateBasicTracking() {
    const result = await stripUserInput("    hello    ");
    console.log('Basic tracking result:', result);
}

OpenAI integration

Weave automatically tracks all OpenAI calls, including:

• Token usage
• API costs
• Request/response pairs
• Model configurations

note

In addition to OpenAI, Weave supports automatic logging of other LLM providers, such as Anthropic and Mistral. For the full list, see LLM Providers in the Integrations documentation.

function initializeOpenAIClient() {
    return weave.wrapOpenAI(new OpenAI({
        apiKey: process.env.OPENAI_API_KEY
    }));
}

async function demonstrateOpenAITracking() {
    const client = initializeOpenAIClient();
    const result = await client.chat.completions.create({
        model: "gpt-4-turbo",
        messages: [{ role: "user", content: "Hello, how are you?" }],
    });
    console.log('OpenAI tracking result:', result);
}

Nested function tracking

Weave allows you to track complex workflows by combining multiple tracked functions and LLM calls while preserving the entire execution trace. The benefits of this include:

• Full visibility into your application's logic flow
• Easy debugging of complex chains of operations
• Performance optimization opportunities

async function demonstrateNestedTracking() {
    const client = initializeOpenAIClient();
    
    const correctGrammar = weave.op(async function correctGrammar(userInput: string): Promise<string> {
        const stripped = await stripUserInput(userInput);
        const response = await client.chat.completions.create({
            model: "gpt-4-turbo",
            messages: [
                {
                    role: "system",
                    content: "You are a grammar checker, correct the following user input."
                },
                { role: "user", content: stripped }
            ],
            temperature: 0,
        });
        return response.choices[0].message.content ?? '';
    });

    const grammarResult = await correctGrammar("That was so easy, it was a piece of pie!");
    console.log('Nested tracking result:', grammarResult);
}

Dataset management

You can create and manage datasets with Weave using the weave.Dataset class. Similar to Weave Models, weave.Dataset helps:

• Track and version your data
• Organize test cases
• Share datasets between team members
• Power systematic evaluations

interface GrammarExample {
    userInput: string;
    expected: string;
}

function createGrammarDataset(): weave.Dataset<GrammarExample> {
    return new weave.Dataset<GrammarExample>({
        id: 'grammar-correction',
        rows: [
            {
                userInput: "That was so easy, it was a piece of pie!",
                expected: "That was so easy, it was a piece of cake!"
            },
            {
                userInput: "I write good",
                expected: "I write well"
            },
            {
                userInput: "LLM's are best",
                expected: "LLM's are the best"
            }
        ]
    });
}

Evaluation framework

Weave supports evaluation-driven development with the Evaluation class. Evaluations help you reliably iterate on your GenAI application. The Evaluation class does the following:

• Assesses Model performance on a Dataset
• Applies custom scoring functions
• Generates detailed performance reports
• Enables comparison between model versions

You can find a complete evaluation tutorial at http://wandb.me/weave_eval_tut

class OpenAIGrammarCorrector {
    private oaiClient: ReturnType<typeof weave.wrapOpenAI>;
    
    constructor() {
        this.oaiClient = weave.wrapOpenAI(new OpenAI({
            apiKey: process.env.OPENAI_API_KEY
        }));
        this.predict = weave.op(this, this.predict);
    }

    async predict(userInput: string): Promise<string> {
        const response = await this.oaiClient.chat.completions.create({
            model: 'gpt-4-turbo',
            messages: [
                { 
                    role: "system", 
                    content: "You are a grammar checker, correct the following user input." 
                },
                { role: "user", content: userInput }
            ],
            temperature: 0
        });
        return response.choices[0].message.content ?? '';
    }
}

async function runEvaluation() {
    const corrector = new OpenAIGrammarCorrector();
    const dataset = createGrammarDataset();
    
    const exactMatch = weave.op(
        function exactMatch({ modelOutput, datasetRow }: { 
            modelOutput: string; 
            datasetRow: GrammarExample 
        }): { match: boolean } {
            return { match: datasetRow.expected === modelOutput };
        },
        { name: 'exactMatch' }
    );

    const evaluation = new weave.Evaluation({
        dataset,
        scorers: [exactMatch],
    });

    const summary = await evaluation.evaluate({
        model: weave.op((args: { datasetRow: GrammarExample }) => 
            corrector.predict(args.datasetRow.userInput)
        )
    });
    console.log('Evaluation summary:', summary);
}

The following main function runs all demonstrations:

async function main() {
    try {
        await initializeWeaveProject();
        await demonstrateBasicTracking();
        await demonstrateOpenAITracking();
        await demonstrateNestedTracking();
        await runEvaluation();
    } catch (error) {
        console.error('Error running demonstrations:', error);
    }
}