eth-rpc-cache/dist/rpc.js

A simple cache for Ethereum RPC requests extensible with different caching strategies

var __assign = (this && this.__assign) || function () {
    __assign = Object.assign || function(t) {
        for (var s, i = 1, n = arguments.length; i < n; i++) {
            s = arguments[i];
            for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
                t[p] = s[p];
        }
        return t;
    };
    return __assign.apply(this, arguments);
};
import pMemoize from 'promise-mem';
import { errors } from './error';
import { perBlockStrategy } from './strategies/per-block';
import { permanentStrategy } from './strategies/permanent';
import { getKey } from './utils/cache-key';
export var createEthRpcCache = function (rpc, options) {
    if (options === void 0) { options = {}; }
    var _a = options.allowOthers, allowOthers = _a === void 0 ? true : _a, _b = options.cache, cache = _b === void 0 ? new Map() : _b, _c = options.strategies, strategies = _c === void 0 ? [perBlockStrategy, permanentStrategy] : _c;
    // Each strategy resolves to a cache if it has a maxAge defined.
    // Index all caches into the object by strategy name
    var cachesByStrategy = strategies
        .filter(function (_a) {
        var maxAge = _a.maxAge;
        return maxAge !== undefined;
    })
        .map(function (_a) {
        var _b;
        var maxAge = _a.maxAge, name = _a.name;
        return (_b = {},
            _b[name] = pMemoize(rpc, __assign({ cache: cache, maxAge: maxAge, resolver: getKey }, options)),
            _b);
    })
        .reduce(function (acc, curr) { return (__assign(__assign({}, acc), curr)); }, {});
    // This object indexed by method holds a function that returns which strategy (and cache)
    // should be used. By default, each strategy resolves to use its own cache, but some strategies
    // may resolve to other strategies' caches, depending on the method
    var strategyResolver = strategies
        .flatMap(function (_a) {
        var methods = _a.methods, name = _a.name, _b = _a.resolver, resolver = _b === void 0 ? function () { return name; } : _b;
        return methods.map(function (method) {
            var _a;
            return (_a = {},
                _a[method] = resolver,
                _a);
        });
    })
        .reduce(function (acc, curr) { return (__assign(__assign({}, acc), curr)); }, {});
    // Return the cached `rpc` function.
    //
    // If an strategy defined an RPC function for the incoming method, use that.
    // Otherwise call the method directly if allowed or return proper errors.
    //
    // To prevent user code to mutate the cached results, the cached RPC functions
    // will always return a clone of the result and not the result object itself.
    return function (method, params) {
        var _a;
        try {
            var strategyName = (_a = strategyResolver[method]) === null || _a === void 0 ? void 0 : _a.call(strategyResolver, method, params);
            if (strategyName) {
                return cachesByStrategy[strategyName](method, params).then(function (c) {
                    // can't inline on .then(structuredClone), TS fails to infer
                    return structuredClone(c);
                });
            }
            if (allowOthers) {
                // not configured to be cached, call the method directly
                return rpc(method, params);
            }
            return Promise.reject(errors.methodNotFound());
        }
        catch (err) {
            // @ts-expect-error error is typed as unknown by default
            return Promise.reject(errors.internalServerError(err));
        }
    };
};