lib/ecc/src/enforce_types.js

export default function enforce(type, value) {
    // Copied from https://github.com/bitcoinjs/bitcoinjs-lib
    switch (type) {
        case "Array": {
            if (Array.isArray(value)) return;
            break;
        }

        case "Boolean": {
            if (typeof value === "boolean") return;
            break;
        }

        case "Buffer": {
            if (Buffer.isBuffer(value)) return;
            break;
        }

        case "Number": {
            if (typeof value === "number") return;
            break;
        }

        case "String": {
            if (typeof value === "string") return;
            break;
        }

        default: {
            if (getName(value.constructor) === getName(type)) return;
        }
    }

    throw new TypeError(
        "Expected " + (getName(type) || type) + ", got " + value
    );
}

function getName(fn) {
    // Why not fn.name: https://kangax.github.io/compat-table/es6/#function_name_property
    var match = fn.toString().match(/function (.*?)\(/);
    return match ? match[1] : null;
}