alagarr/dist/src/response/middleware/etag.js

Alagarr is a request-response helper library that removes the boilerplate from your Node.js serverless functions and helps make your code portable.

"use strict";
var __importStar = (this && this.__importStar) || function (mod) {
    if (mod && mod.__esModule) return mod;
    var result = {};
    if (mod != null) for (var k in mod) if (Object.hasOwnProperty.call(mod, k)) result[k] = mod[k];
    result["default"] = mod;
    return result;
};
Object.defineProperty(exports, "__esModule", { value: true });
const crypto = __importStar(require("crypto"));
exports.EMPTY_ENTITY_TAG = '"0-2jmj7l5rSw0yVb/vlWAYkK/YBwk"';
function entitytag(entity) {
    const hash = crypto
        .createHash('sha1')
        .update(entity, 'utf8')
        .digest('base64')
        .substring(0, 27);
    const length = typeof entity === 'string'
        ? Buffer.byteLength(entity, 'utf8')
        : entity.length;
    return `"${length.toString(16)}-${hash}"`;
}
function etag(entity) {
    return entity.length === 0 ? exports.EMPTY_ENTITY_TAG : entitytag(entity);
}
function etagHeader(response) {
    return Object.assign({}, response, { headers: Object.assign({}, response.headers, { etag: etag(response.body) }) });
}
exports.default = etagHeader;