@nestjs/microservices/utils/transform-pattern.utils.js

Nest - modern, fast, powerful node.js web framework (@microservices)

import { isObject, isString, isNumber } from '@nestjs/common/internal';
const DEFAULT_MAX_DEPTH = 5;
const DEFAULT_MAX_KEYS = 20;
const DEFAULT_MAX_KEY_LENGTH = 256;
const escape = (s) => s.replace(/\\/g, '\\\\').replace(/"/g, '\\"');
/**
 * Transforms the Pattern to Route safely.
 *
 * @param pattern - client pattern
 * @param depth - current recursion depth
 * @param maxDepth - maximum allowed recursion depth
 * @param maxKeys - maximum allowed keys per object
 * @param maxKeyLength - maximum allowed length of a key
 * @returns string
 */
export function transformPatternToRoute(pattern, depth = 0, maxDepth = DEFAULT_MAX_DEPTH, maxKeys = DEFAULT_MAX_KEYS, maxKeyLength = DEFAULT_MAX_KEY_LENGTH) {
    if (isString(pattern) || isNumber(pattern)) {
        return `${pattern}`;
    }
    if (!isObject(pattern)) {
        // For non-string, non-number, non-object values
        return pattern;
    }
    if (depth > maxDepth) {
        return '[MAX_DEPTH_REACHED]';
    }
    const keys = Object.keys(pattern);
    if (keys.length > maxKeys) {
        return '[TOO_MANY_KEYS]';
    }
    // localeCompare can take time quadratic in the length of the keys
    if (keys.some(key => key.length > maxKeyLength)) {
        return '[KEY_TOO_LONG]';
    }
    const sortedKeys = keys.sort((a, b) => ('' + a).localeCompare(b));
    const parts = sortedKeys.map(key => {
        const value = pattern[key];
        let partialRoute = `"${escape(key)}":`;
        // Only quote strings, numbers and objects are handled recursively
        if (isString(value)) {
            partialRoute += `"${escape(transformPatternToRoute(value, depth + 1, maxDepth, maxKeys, maxKeyLength))}"`;
        }
        else {
            partialRoute += transformPatternToRoute(value, depth + 1, maxDepth, maxKeys, maxKeyLength);
        }
        return partialRoute;
    });
    return `{${parts.join(',')}}`;
}