Get SharePoint Document Library Size

function sleep(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
}

async function GetFolderSize(siteUrl, listUrl1, query) {
    // Fetch options with headers for authentication and response format
    const fetchOptions = {
        method: 'GET',
        headers: {
            'Accept': 'application/json;odata=verbose'
        }
    };
    // get web relativeUrl
    var req = `${siteUrl}/_api/web?$select=ServerRelativeUrl`;
    const webServerRelativUrl = (await (await fetch(req, fetchOptions)).json()).d.ServerRelativeUrl;
    let query1 = "";
    if (`${query}`.trim() !== "") {
        query1 = `&$filter=${query}`;
        query = ` and ${query}`;
    }
    // get firstId
    req = `${siteUrl}/_api/web/getlist('${webServerRelativUrl}/${listUrl1}')/items?$select=Id&$top=1&$orderby=Id asc`;
    console.log("req", req);
    const firstId = 0;
    console.log("firstId", firstId);
    // get lastId
    req = `${siteUrl}/_api/web/getlist('${webServerRelativUrl}/${listUrl1}')/items?$select=Id&$top=1&$orderby=Id desc`;
    console.log("last", req);
    const lastId = (await (await fetch(req, fetchOptions)).json()).d.results[0].Id;
    console.log("lastId", lastId);
    let startId = firstId;
    let endId = firstId + 5000;
    var allItems = [];
    console.log(`startId ${startId} endId ${endId} lastId ${lastId}`);
    console.log("query", query);
    const startDate = new Date();
    let endDate = new Date();
    let diffMinutes = 0;
    let queryNumber = 0;
    do {
        // to avoid 429 error
        if(queryNumber % 10 == 0){
            await sleep(60000); // 60 000 ms = 1 minute
        }
        var select = "?$select=File/Length";
        req = `${siteUrl}/_api/web/getlist('${webServerRelativUrl}/${listUrl1}')/items${select}&$filter=Id ge ${startId} and Id lt ${endId}${query}&$orderby=Id asc&$top=5000&$expand=File`;
        console.log("req", req);
        let respList1 = null;
        try {
            respList1 = await fetch(req, fetchOptions);
            if (!respList1.ok) {
                const errorDetails = await respList1.text();
                console.error(`HTTP error! Status: ${respList1.status}, Details: ${errorDetails}`);
                let err = JSON.parse(errorDetails);
                console.error(`HTTP error! Status: ${respList1.status}, Details: ${err.error.message.value}`);
                console.log(err.error.message.value);
                throw new Error(`HTTP error! Status: ${respList1.status}`);
            }
            endDate = new Date();
            queryNumbercatch (error) {
            console.log("error", error);
            return null;
        }
        const items = (await respList1.json()).d.results;
        allItems.push(...items);
        startId += 5000;
        endId += 5000;
        const diffMs = endDate - startDate;
        diffMinutes = Math.floor(diffMs / (1000 * 60));
        console.log(`startId ${startId} endId ${endId} lastId ${lastId} diffMinutes ${diffMinutes} queryNumber  ${queryNumber}`)
    }
    while (endId < lastId);
    console.log("queryNumber", queryNumber);
    return allItems;
}
let totalSize = 0
const siteUrl = "Your site Url";
const items = await GetFolderSize(siteUrl, "Your doclib Name", "startswith(ContentTypeId,'0x0101')");
// calculate file Size
for (let i = 0; i < items.length; i++) {
    if (items[i].File != undefined && items[i].File.Length != undefined) {
        totalSize += parseInt(items[i].File.Length);
    }
}
const totalSizeGB = (totalSize / (1024 * 1024 * 1024)).toFixed(2);
console.log("totalSize   B", totalSize);
console.log("total size MB", (totalSize / (1024 * 1024)).toFixed(2));
console.log("total size GB", totalSizeGB);
console.log("items length", items.length);

        

function sleep(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
}
async function GetFolderSize(siteUrl, listUrl1, query) {
    // Fetch options with headers for authentication and response format
    const fetchOptions = {
        method: 'GET',
        headers: {
            'Accept': 'application/json;odata=verbose'
        }
    };

    //get web relativeUrl
    var req = `${siteUrl}/_api/web?$select=ServerRelativeUrl`;
    const webServerRelativUrl = (await (await fetch(req, fetchOptions)).json()).d.ServerRelativeUrl;

    let query1 = "";
    if (`${query}`.trim() !== "") {
        query1 = `&$filter=${query}`;
        query = ` and ${query}`;
    }
    //get firstId
    req = `${siteUrl}/_api/web/getlist('${webServerRelativUrl}/${listUrl1}')/items?$select=Id&$top=1&$orderby=Id asc`;
    console.log("req", req);
    const firstId = 0;
    console.log("firstId", firstId);
    //get lastId
    req = `${siteUrl}/_api/web/getlist('${webServerRelativUrl}/${listUrl1}')/items?$select=Id&$top=1&$orderby=Id desc`;
    console.log("last", req);
    const lastId = (await (await fetch(req, fetchOptions)).json()).d.results[0].Id;
    console.log("lastId", lastId);


    let startId = firstId;
    let endId = firstId + 5000;
    var allItems = [];

    console.log(`startId ${startId} endId ${endId} lastId ${lastId}`);//FileSizeDisplay
    console.log("query", query);//_UIVersionString File_x0020_Size
    const startDate = new Date();
    let endDate = new Date();
    let diffMinutes = 0;
    let queryNumber = 0;
    do {
        //to avoid 429 error
        if(queryNumber % 10 == 0){
            await sleep(60000); // 60 000 ms = 1 minute
        }
        var select = "?$select=File/Length";
        req = `${siteUrl}/_api/web/getlist('${webServerRelativUrl}/${listUrl1}')/items${select}&$filter=Id ge ${startId} and Id lt ${endId}${query}&$orderby=Id asc&$top=5000&$expand=File`;
        console.log("req", req);
        // Send the asynchronous GET request to the REST API endpoint /_api/site/usage
        let respList1 = null;
        try {
            respList1 = await fetch(req, fetchOptions);

            if (!respList1.ok) {
                const errorDetails = await respList1.text(); // Get error details from the response
                console.error(`HTTP error! Status: ${respList1.status}, Details: ${errorDetails}`);
                let err = JSON.parse(errorDetails);
                console.error(`HTTP error! Status: ${respList1.status}, Details: ${err.error.message.value}`);
                console.log(err.error.message.value);
                throw new Error(`HTTP error! Status: ${respList1.status}`);
            }
            endDate = new Date();
            queryNumber++;
        } catch (error) {
            console.log("error", error);
            return null;
        }
        const items = (await respList1.json()).d.results;
        allItems.push(...items);
        startId += 5000;
        endId += 5000;
        const diffMs = endDate - startDate;
        diffMinutes = Math.floor(diffMs / (1000 * 60));
        console.log(`startId ${startId} endId ${endId} lastId ${lastId} diffMinutes ${diffMinutes} queryNumber  ${queryNumber}`)
    }
    while (endId < lastId);

    //console.log("allItems", allItems);
    console.log("queryNumber", queryNumber);
    return allItems;
}
let totalSize = 0


const siteUrl = "Your site Url";

const items = await GetFolderSize(siteUrl, "Your doclib Name", "startswith(ContentTypeId,'0x0101')");


//calculate file Size
for (let i = 0; i < items.length; i++) {

    if (items[i].File != undefined && items[i].File.Length != undefined) {
        totalSize += parseInt(items[i].File.Length);
    }
}
const totalSizeGB = (totalSize / (1024 * 1024 * 1024)).toFixed(2);
console.log("totalSize   B", totalSize);
console.log("total size MB", (totalSize / (1024 * 1024)).toFixed(2));
console.log("total size GB", totalSizeGB);


console.log("items length", items.length);
//console.log("items", items);