@sudowealth/schwab-api/dist/src/middleware/compose.js

TypeScript client for Charles Schwab API with OAuth support, market data, trading functionality, and complete type safety

export function compose(...mws) {
    return (initial) => {
        // Ensure fetch is available in the global scope or polyfilled
        const effectiveFetch = typeof fetch !== 'undefined' ? fetch : globalThis.fetch;
        if (!effectiveFetch) {
            throw new Error('Global fetch is not available. Please provide a fetch polyfill.');
        }
        // Create a fetch function to use as the final handler in the middleware chain
        const fetchHandler = (req) => {
            return effectiveFetch(req);
        };
        // Build middleware chain from right to left (last to first)
        const handler = mws.reduceRight((nextHandler, middleware) => {
            // Create a new handler that applies this middleware with the next handler
            return (req) => {
                return middleware(req, nextHandler);
            };
        }, fetchHandler);
        // Execute the composed handler chain with the initial request
        return handler(initial);
    };
}