@eagleoutice/flowr-dev/util/text/url-encoding.js

Static Dataflow Analyzer and Program Slicer for the R Programming Language

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.toBase64 = toBase64;
exports.toBase64Url = toBase64Url;
exports.fromBase64Url = fromBase64Url;
exports.packForUrl = packForUrl;
exports.unpackFromUrl = unpackFromUrl;
const lz_string_1 = require("lz-string");
/**
 * Base64 for the pages flowR ships, which run in a browser and therefore have `btoa`/`atob` rather than
 * node's `Buffer`. The url-safe pair is what lets the playground keep a script in its own address, so a
 * link is the example.
 */
/** bytes as base64 */
function toBase64(bytes) {
    let binary = '';
    for (const byte of bytes) {
        binary += String.fromCharCode(byte);
    }
    return btoa(binary);
}
/** text as base64 in the alphabet a url carries without escaping anything, padding dropped */
function toBase64Url(text) {
    return toBase64(new TextEncoder().encode(text)).replaceAll('+', '-').replaceAll('/', '_').replace(/=+$/, '');
}
/** the inverse of {@link toBase64Url}, `undefined` for anything that is not what it produced */
function fromBase64Url(text) {
    try {
        const binary = atob(text.replaceAll('-', '+').replaceAll('_', '/'));
        return new TextDecoder('utf-8', { fatal: true }).decode(Uint8Array.from(binary, character => character.charCodeAt(0)));
    }
    catch {
        return undefined; /* a link someone edited by hand */
    }
}
/** Text as short as it goes while staying a url: compressed when that helps, plain base64 when it does not. */
function packForUrl(text) {
    const plain = toBase64Url(text);
    if (text.length === 0) {
        return "t" /* Packing.Plain */ + plain;
    }
    const compressed = (0, lz_string_1.compressToEncodedURIComponent)(text);
    return compressed.length < plain.length ? "z" /* Packing.Compressed */ + compressed : "t" /* Packing.Plain */ + plain;
}
/** The inverse of {@link packForUrl}, `undefined` for anything it did not produce. */
function unpackFromUrl(payload) {
    const rest = payload.slice(1);
    try {
        switch (payload[0]) {
            case "z" /* Packing.Compressed */: return (0, lz_string_1.decompressFromEncodedURIComponent)(rest) ?? undefined;
            case "t" /* Packing.Plain */: return fromBase64Url(rest);
            default: return undefined;
        }
    }
    catch {
        return undefined; /* a link someone edited by hand */
    }
}
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