function getContentFromDataUrl(dataURL) {
    return dataURL.split(/,/)[1];
}
function isDataUrl(url) {
    return url.search(/^(data:)/) !== -1;
}
function makeDataUrl(content, mimeType) {
    return `data:${mimeType};base64,${content}`;
}
async function fetchAsDataURL(url, init, process) {
    const res = await fetch(url, init);
    if (res.status === 404) {
        throw new Error(`Resource "${res.url}" not found`);
    }
    const blob = await res.blob();
    return new Promise((resolve, reject) => {
        const reader = new FileReader();
        reader.onerror = reject;
        reader.onloadend = () => {
            try {
                resolve(process({ res, result: reader.result }));
            }
            catch (error) {
                reject(error);
            }
        };
        reader.readAsDataURL(blob);
    });
}
const cache = {};
function getCacheKey(url, contentType, includeQueryParams) {
    let key = url.replace(/\?.*/, '');
    if (includeQueryParams) {
        key = url;
    }
    // font resource
    if (/ttf|otf|eot|woff2?/i.test(key)) {
        key = key.replace(/.*\//, '');
    }
    return contentType ? `[${contentType}]${key}` : key;
}
async function resourceToDataURL(resourceUrl, contentType, options) {
    const cacheKey = getCacheKey(resourceUrl, contentType, options.includeQueryParams);
    if (cache[cacheKey] != null) {
        return cache[cacheKey];
    }
    // ref: https://developer.mozilla.org/en/docs/Web/API/XMLHttpRequest/Using_XMLHttpRequest#Bypassing_the_cache
    if (options.cacheBust) {
        // eslint-disable-next-line no-param-reassign
        resourceUrl += (/\?/.test(resourceUrl) ? '&' : '?') + new Date().getTime();
    }
    let dataURL;
    try {
        const content = await fetchAsDataURL(resourceUrl, options.fetchRequestInit, ({ res, result }) => {
            if (!contentType) {
                // eslint-disable-next-line no-param-reassign
                contentType = res.headers.get('Content-Type') || '';
            }
            return getContentFromDataUrl(result);
        });
        dataURL = makeDataUrl(content, contentType);
    }
    catch (error) {
        dataURL = options.imagePlaceholder || '';
        let msg = `Failed to fetch resource: ${resourceUrl}`;
        if (error) {
            msg = typeof error === 'string' ? error : error.message;
        }
        if (msg) {
            console.warn(msg);
        }
    }
    cache[cacheKey] = dataURL;
    return dataURL;
}

export { fetchAsDataURL, isDataUrl, makeDataUrl, resourceToDataURL };
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