@remix-run/headers/dist/lib/if-range.js

A toolkit for working with HTTP headers in JavaScript

import {} from "./header-value.js";
import { parseHttpDate, removeMilliseconds } from "./utils.js";
import { quoteEtag } from "./utils.js";
/**
 * The value of an `If-Range` HTTP header.
 *
 * The `If-Range` header can contain either an entity tag (ETag) or an HTTP date.
 *
 * [MDN `If-Range` Reference](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/If-Range)
 *
 * [HTTP/1.1 Specification](https://datatracker.ietf.org/doc/html/rfc7233#section-3.2)
 */
export class IfRange {
    value = '';
    /**
     * @param init A string or Date to initialize the header
     */
    constructor(init) {
        if (init) {
            if (typeof init === 'string') {
                this.value = init;
            }
            else {
                this.value = init.toUTCString();
            }
        }
    }
    /**
     * Checks if the `If-Range` condition is satisfied for the current resource state.
     *
     * This method always returns `true` if the `If-Range` header is not present,
     * meaning the range request should proceed unconditionally.
     *
     * The `If-Range` header can contain either:
     * - An HTTP date (RFC 7231 IMF-fixdate format)
     * - An entity tag (ETag)
     *
     * When comparing ETags, only strong entity tags are matched as per RFC 7233.
     * Weak entity tags (prefixed with `W/`) are never considered a match.
     *
     * @param resource The current resource state to compare against
     * @return `true` if the condition is satisfied, `false` otherwise
     *
     * @example
     * ```ts
     * let ifRange = new IfRange('Wed, 21 Oct 2015 07:28:00 GMT')
     * ifRange.matches({ lastModified: 1445412480000 }) // true if dates match
     * ifRange.matches({ lastModified: new Date('2015-10-21T07:28:00Z') }) // true
     *
     * let ifRange2 = new IfRange('"abc123"')
     * ifRange2.matches({ etag: '"abc123"' }) // true
     * ifRange2.matches({ etag: 'W/"abc123"' }) // false (weak ETag)
     * ```
     */
    matches(resource) {
        if (!this.value) {
            return true;
        }
        // Try parsing as HTTP date first
        let dateTimestamp = parseHttpDate(this.value);
        if (dateTimestamp !== null && resource.lastModified != null) {
            return removeMilliseconds(dateTimestamp) === removeMilliseconds(resource.lastModified);
        }
        // Otherwise treat as ETag
        if (resource.etag != null) {
            let normalizedTag = quoteEtag(this.value);
            let normalizedResourceTag = quoteEtag(resource.etag);
            // Weak tags never match in If-Range (strong comparison only, per RFC 7233)
            if (normalizedTag.startsWith('W/') || normalizedResourceTag.startsWith('W/')) {
                return false;
            }
            return normalizedTag === normalizedResourceTag;
        }
        return false;
    }
    /**
     * Returns the string representation of the header value.
     *
     * @return The header value as a string
     */
    toString() {
        return this.value;
    }
}