@worker-tools/json-stream/esm/json-stringify.js

Utilities for working with streaming JSON in Worker Runtimes such as Cloudflare Workers, Deno Deploy and Service Workers.

// deno-lint-ignore-file no-explicit-any no-empty
import { asyncIterToStream } from 'whatwg-stream-to-async-iter';
export const isIterable = (x) => x != null && typeof x === 'object' && Symbol.iterator in x;
export const isAsyncIterable = (x) => x != null && typeof x === 'object' && Symbol.asyncIterator in x;
const isPromiseLike = (x) => x != null && typeof x === 'object' && 'then' in x && typeof x.then === 'function';
const isToJSON = (x) => x != null && typeof x === 'object' && 'toJSON' in x;
const safeAdd = (seen, value) => {
    if (seen.has(value))
        throw TypeError('Converting circular structure to JSON');
    seen.add(value);
};
const check = (v) => {
    if (v === undefined)
        return false;
    const type = typeof v;
    return type !== 'function' && type !== 'symbol';
};
// TODO: Add replacer
// TODO: add formatting/spaces
// TODO: concurrent objects/arrays
/**
 * @deprecated Change name to something more descriptive!?
 */
export async function* jsonStringifyGenerator(value, seen = new WeakSet()) {
    if (isAsyncIterable(value)) {
        yield '[';
        safeAdd(seen, value);
        let first = true;
        for await (const v of value) {
            if (!first)
                yield ',';
            else
                first = false;
            yield* jsonStringifyGenerator(v, seen);
        }
        seen.delete(value);
        yield ']';
    }
    else if (isPromiseLike(value)) {
        const v = await value;
        if (check(v)) {
            safeAdd(seen, value);
            yield* jsonStringifyGenerator(v, seen);
            seen.delete(value);
        }
    }
    else if (isToJSON(value)) {
        const v = JSON.stringify(value);
        if (check(v))
            yield v;
    }
    else if (Array.isArray(value)) {
        yield '[';
        safeAdd(seen, value);
        let first = true;
        for (const v of value) {
            if (!first)
                yield ',';
            else
                first = false;
            yield* jsonStringifyGenerator(v, seen);
        }
        seen.delete(value);
        yield ']';
    }
    else if (value != null && typeof value === 'object') {
        yield '{';
        safeAdd(seen, value);
        let first = true;
        for (const [k, v] of Object.entries(value)) {
            if (check(v)) {
                const generator = jsonStringifyGenerator(v, seen);
                const peek = await generator.next();
                if (check(peek.value)) {
                    if (!first)
                        yield ',';
                    else
                        first = false;
                    yield `${JSON.stringify(k)}:`;
                    yield peek.value;
                    yield* generator;
                }
            }
        }
        seen.delete(value);
        yield '}';
    }
    else {
        yield check(value) ? JSON.stringify(value) : 'null';
    }
}
/**
 * @deprecated Change name to something more descriptive!?
 */
export function jsonStringifyStream(value) {
    return asyncIterToStream(jsonStringifyGenerator(value));
}
export class JSONStringifyReadable extends ReadableStream {
    constructor(value) {
        let iterator;
        super({
            start() {
                iterator = jsonStringifyGenerator(value)[Symbol.asyncIterator]();
            },
            async pull(controller) {
                // console.log('stringify', controller.desiredSize)
                const { value, done } = await iterator.next();
                if (!done)
                    controller.enqueue(value);
                else
                    controller.close();
            },
            async cancel(reason) {
                var _a;
                try {
                    await ((_a = iterator.throw) === null || _a === void 0 ? void 0 : _a.call(iterator, reason));
                }
                catch { }
            },
        });
    }
}
//# sourceMappingURL=json-stringify.js.map