RESTful WIQL Interface for Azure DevOps Extension SDK

I'm writing an Azure DevOps extension using the azure-devops-extension-sdk in React.js. I'm trying to query our existing Product Backlog Items for one with a matching title to get the id for that PBI and update the description as I add new tasks to it.

Is this something that's possible in the Azure DevOps Extension SDK or do I need to import a different library for this interface?

I can't seem to find any documentation on how to authenticate and interface with Azure DevOps Services API. I haven't found much in regards to authentication. I've found documentation on what endpoint to use to run my WIQL query and how to format the payload, but I can't find the SDK methods to accomplish those requests.

This documentation points back to the VSS Web Extension SDK, not the current Azure DevOps Extension SDK. https://learn.microsoft.com/en-us/rest/api/azure/devops/?view=azure-devops-rest-7.2&viewFallbackFrom=azure-devops-rest-7.0

Other documentation refers to utilizing C#, but extensions are written utilizing React.js and TypeScript.

Well, someone offered an answer that has since been deleted which pointed me in the right direction.

This retrieves the access token:

async function getAuthToken() {
    try {
        const token = await SDK.getAccessToken();
        return token;
    } catch (error) {
        console.error("Failed to get access token", error);
    }
    return "";
}

This runs a query against your work items:

async function queryWorkItems(token: string, query: string, devopsProjectName: string, devopsUrl: string) {

    const response = await fetch(`${devopsUrl}/${devopsProjectName}/_apis/wit/wiql?api-version=7.2-preview.2`, {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'Authorization': `Bearer ${token}`
        },
        body: JSON.stringify({ query })
    });

    if (!response.ok) {
        throw new Error(`Error querying work items: ${response.statusText}`);
    }

    const result = await response.json();
    return result.workItems;
}

This will pull a single work item (to get the current values like System.Description):

async function getWorkItem(token: string, workItemId: string, devopsProjectName: string, devopsUrl: string) {

    const response = await fetch(`${devopsUrl}/${devopsProjectName}/_apis/wit/workitems/${workItemId}?api-version=7.2-preview.2`, {
        method: 'GET',
        headers: {
            'Content-Type': 'application/json-patch+json',
            'Authorization': `Bearer ${token}`
        }
    });

    if (!response.ok) {
        throw new Error(`Error getting work item # ${workItemId}: ${response.statusText}`);
    }

    const result = await response.json();
    return result;
}

This will update an existing work item:

async function updateWorkItem(token: string, workItemId: string, description: string, newDescription: string, devopsProjectName: string, devopsUrl: string) {

    const fields = [
        {
            op: Operation.Add,
            from: "",
            path: "/fields/System.Description",
            value: description + newDescription
        }
    ];
    const response = await fetch(`${devopsUrl}/${devopsProjectName}/_apis/wit/workitems/${workItemId}?api-version=7.2-preview.2`, {
        method: 'PATCH',
        headers: {
            'Content-Type': 'application/json-patch+json',
            'Authorization': `Bearer ${token}`
        },
        body: JSON.stringify(fields)
    });

    if (!response.ok) {
        throw new Error(`Error updating work item: ${response.statusText}`);
    }

    const result = await response.json();
    return result;
}

So, to pull all of those together, I'm using this function to find my work item, update the description, and return the id:

async function findAndUpdateWorkItemByTitle(title: string, newDescription: string, devopsProjectName: string, devopsUrl: string) {
    try {
        const token = await getAuthToken();

        const query = `SELECT [Id], [Description] FROM workitems WHERE [System.Title] = '${title}'`;
        const workItems = await queryWorkItems(token, query, devopsProjectName, devopsUrl);

        if (workItems.length === 0) {
            console.log("No work item found with the given title.");
            return "0";
        }

        const workItemId: string = workItems[0].id;

        var workItem = await getWorkItem(token, workItemId, devopsProjectName, devopsUrl);


        const updatedWorkItem = await updateWorkItem(token, workItemId, workItem.fields["System.Description"], newDescription, devopsProjectName, devopsUrl);
        return workItemId;
    } catch (error) {
        console.log("Could not update existing item.");
        console.error("Error:", error);
    }
    return "0";
}

I'm still optimizing this, but this was the quick solution to get it working. Thank you to whomever posted the basis for this which pushed me in the right direction.