Interface Logger

A logger interface. It is inspired from the interface and behavior of the org.slf4j.Logger API.

Example: <caption>Log debug message</caption>

  import { loggerForName } from "apprt-core/Logger";
  const LOG = loggerForName("mybundle/MyFile");
  LOG.debug("Component started");

Example: <caption>Use placeholders</caption>

  import { loggerForName } from "apprt-core/Logger";
  const LOG = loggerForName("mybundle/MyFile");
  const name = "Xyz";
  LOG.debug("Component '{}' started", name);
     // -> logs "Component 'Xyz' started"

Example: <caption>Test wether log level is enabled</caption>

  import { loggerForName } from "apprt-core/Logger";
  const LOG = loggerForName("mybundle/MyFile");

  if (LOG.isDebugEnabled()){
     LOG.debug("did something");
  }

Example: <caption>Log prefixed messages</caption>

  import { loggerForName } from "apprt-core/Logger";
  const LOG = loggerForName("mybundle/MyFile");
  const LOGWithPrefix = LOG.withPrefix("[my prefix]");
  LOGWithPrefix.info("My Message");
     // -> logs "[my prefix] My Message"
interface Logger {
    debug(msg: string, ...args: any[]): void;
    error(msg: string, ...args: any[]): void;
    error(error: Error): void;
    getLevel(): LogLevel;
    getName(): string;
    info(msg: string, ...args: any[]): void;
    isDebugEnabled(): boolean;
    isErrorEnabled(): boolean;
    isInfoEnabled(): boolean;
    isLevelEnabled(level: LogLevel): boolean;
    isWarnEnabled(): boolean;
    warn(msg: string, ...args: any[]): void;
    warn(error: Error): void;
    withPrefix(prefix: string): Logger;
}

Methods

debug error getLevel getName info isDebugEnabled isErrorEnabled isInfoEnabled isLevelEnabled isWarnEnabled warn withPrefix

Methods

debug

  • debug(msg: string, ...args: any[]): void

  • Log a message at level DEBUG.

    The message may contain one or more placeholders '{}', which are replaced by the string value of the given arguments.

    Note that placeholders are always replaced and can not be escaped at the moment.

    If the list of arguments is longer than the number of placeholders in the given message, each remaining argument is logged in a separate log statement.

    Parameters

    • msg: string

      the message, may contain '{}' placeholders.

    • ...args: any[]

      arguments filled into the placeholder or directly logged.

    Returns void

error

  • error(msg: string, ...args: any[]): void

  • Log a message at level ERROR.

    Similar to debug except for the used log level.

    Parameters

    • msg: string

      the message, may contain '{}' placeholders.

    • ...args: any[]

      arguments filled into the placeholder or directly logged.

    Returns void

  • error(error: Error): void

  • Convenience method to log an error (without an additional message) as an error.

    Parameters

    • error: Error

      the error to log

    Returns void

getLevel

  • getLevel(): LogLevel

  • Lookup the current logger level.

    Returns LogLevel

getName

  • getName(): string

  • Get the current logger name.

    Returns string

info

  • info(msg: string, ...args: any[]): void

  • Log a message at level INFO.

    Similar to debug except for the used log level.

    Parameters

    • msg: string

      the message, may contain '{}' placeholders.

    • ...args: any[]

      arguments filled into the placeholder or directly logged.

    Returns void

isDebugEnabled

  • isDebugEnabled(): boolean

  • Is DEBUG level enabled for this logger.

    Returns boolean

isErrorEnabled

  • isErrorEnabled(): boolean

  • Is ERROR level enabled for this logger.

    Returns boolean

isInfoEnabled

  • isInfoEnabled(): boolean

  • Is INFO level enabled for this logger.

    Returns boolean

isLevelEnabled

  • isLevelEnabled(level: LogLevel): boolean

  • Is given level enabled for this logger.

    Parameters

    Returns boolean

isWarnEnabled

  • isWarnEnabled(): boolean

  • Is WARN level enabled for this logger.

    Returns boolean

warn

  • warn(msg: string, ...args: any[]): void

  • Log a message at level WARN.

    Similar to debug except for the used log level.

    Parameters

    • msg: string

      the message, may contain '{}' placeholders.

    • ...args: any[]

      arguments filled into the placeholder or directly logged.

    Returns void

  • warn(error: Error): void

  • Convenience method to log an error (without an additional message) as a warning.

    Parameters

    • error: Error

      the error to log

    Returns void

withPrefix

  • withPrefix(prefix: string): Logger

  • Creates a new Logger, which will prefix each log message with the given prefix.

    Parameters

    • prefix: string

      a prefix

    Returns Logger

    Example: <caption>Log prefixed messages</caption>

      const LOG = loggerForName("mybundle/MyFile");
      const LOGWithPrefix = LOG.withPrefix("[my prefix]");
      LOGWithPrefix.info("My Message");
         // -> logs "[my prefix] My Message"

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