Class Logger

packages/core-backend/src/logger.ts:19–114

const logLevels: Array<LogLevel> = ["log", "error", "warn", "info", "debug"];

export class Logger {
  #name: string;
  readonly #level: number;
  #filteredKeys: string[] = [];
  #jsonReplacer?: (key: string, value: unknown) => unknown;
  #additionalFields: () => Record<string, unknown>;

  constructor(
    name: string,
    level: LogLevel = "info",
    filteredKeys: string[] = [],
    jsonReplacer?: (key: string, value: unknown) => unknown,
    additionalFields?: () => Record<string, unknown>
  ) {
    this.#name = name;
    this.#level = logLevels.indexOf((env.TRIGGER_LOG_LEVEL ?? level) as LogLevel);
    this.#filteredKeys = filteredKeys;
    this.#jsonReplacer = createReplacer(jsonReplacer);
    this.#additionalFields = additionalFields ?? (() => ({}));
  }

  child(fields: Record<string, unknown>) {
    return new Logger(
      this.#name,
      logLevels[this.#level],
      this.#filteredKeys,
      this.#jsonReplacer,
      () => ({ ...this.#additionalFields(), ...fields })
    );
  }

  // Return a new Logger instance with the same name and a new log level
  // but filter out the keys from the log messages (at any level)
  filter(...keys: string[]) {
    return new Logger(this.#name, logLevels[this.#level], keys, this.#jsonReplacer);
  }

  static satisfiesLogLevel(logLevel: LogLevel, setLevel: LogLevel) {
    return logLevels.indexOf(logLevel) <= logLevels.indexOf(setLevel);
  }

  log(message: string, ...args: Array<Record<string, unknown> | undefined>) {
    if (this.#level < 0) return;

    this.#structuredLog(console.log, message, "log", ...args);
  }

  error(message: string, ...args: Array<Record<string, unknown> | undefined>) {
    if (this.#level < 1) return;

    this.#structuredLog(console.error, message, "error", ...args);
  }

  warn(message: string, ...args: Array<Record<string, unknown> | undefined>) {
    if (this.#level < 2) return;

    this.#structuredLog(console.warn, message, "warn", ...args);
  }