@egomobile/log-filter

Extension for js-log with utilities to handle extended filters.

Install

Execute the following command from your project folder, where your package.json file is stored:

npm install --save @egomobile/log-filter

The following modules are defined in peerDependencies and have to be installed manually:

• @egomobile/log

Usage

Quick example

import log from "@egomobile/log";
import { withFilterExpression } from "@egomobile/log-filter";

// only warning or errors
const expression = 'severity == "warn" or severity == "error"';

log.use(withFilterExpression(expression));

// will log
log.warn("foo");
log.error("foo");

// will not log:
log("foo");
log.debug("foo");
log.info("foo");
log.trace("foo");

Syntax

The syntax is described here.

Constants

| Name | Description | Example | | ----------- | ------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------- | | args | An array with all arguments, which were submitted to log function. | "foo" in args | | debug | Value of LogType.Debug. | type == debug | | default | Value of LogType.Default. | type == default | | error | Value of LogType.Error. | type == error | | false | Value of false. | isDebug == false | | info | Value of LogType.Info. | type == info | | isDebug | Indicates if type has value of LogType.Debug. | isDebug and type == debug | | isDefault | Indicates if type has value of LogType.Default. | isDefault and type == default | | isError | Indicates if type has value of LogType.Error. | isError and type == error | | isInfo | Indicates if type has value of LogType.Info. | isInfo and type == info | | isTrace | Indicates if type has value of LogType.Trace. | isTrace and type == trace | | isWarn | Indicates if type has value of LogType.Warn. | isWarn and type == warn | | null | Value of null. | arg0 != null | | severity | type as string in lower case characters. | severity in ("debug", "default", "error", "info", "trace", "warn") | | trace | Value of LogType.Trace. | type == trace | | true | Value of true. | isError == true | | type | A value of LogType. | type not in (debug, trace) | | undefined | Value of undefined. | arg0 != undefined | | warn | Value of LogType.Warn. | type == warn |

Additionally there will also dynamic constants be added, based on the number of arguments, which are submitted to a log function:

// arg0 == "foo" and message0 == "foo"
// arg1 == 42 and message1 == "42"
// arg2 == false and message2 == "false"
// arg3 == null and message3 == ""
// arg4 == undefined and message4 == ""
log("foo", 42, false, null, undefined);

It is also possible to add extra constants:

import log, { LogType } from "@egomobile/log";
import {
  IGetExtraLogFilterConstantsContext,
  LogFilterConstants,
  withFilterExpression,
} from "@egomobile/log-filter";

const expression =
  'foo == 42 and lowerMessage1 == "foo bar baz" and upperSeverity == "WARN" and error == undefined';

log.use(
  withFilterExpression(expression, {
    getExtraConstants: ({ type, args }: IGetExtraLogFilterConstantsContext) => {
      const extraConstants: LogFilterConstants = {
        // static value
        foo: 42,
        // functions will be handled as getters
        upperSeverity: () => LogType[type].toUpperCase(),
        // remove constant
        error: undefined,
      };

      // add extra and dynamic constants
      // lowerMessage<index + 1>
      // with lowercase values of items
      // of 'args'
      args.forEach((a, index) => {
        extraConstants[`lowerMessage${index + 1}`] = String(a).toLowerCase();
      });

      return extraConstants;
    },
  })
);

// should log
log.warn("FOO BAR BAZ");

// should not log
log("FOO BAR BAZ");
log.warn("FUH BAR BAZZ");

Functions

| Name | Description | Example | | ------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------- | | concat(..args: any[]) | Handles a list of arguments as strings and concats them to one without using a separator. | concat("Tanja", " M.") == "Tanja M." | | day(useLocalTimeOrTimezone: boolean \| string) | Returns the current day of the current month. | day() >= 1 and day() <= 31 | | endOf(value: any, unit: string, useLocalTimeOrTimezone: boolean \| string) | Returns a value, which represents the end of a time area. | endOf(now(), "day") >= now() | | every(value: any, ...args: any[]) | Handles a value as string and checks if all arguments are included. | every("foo Bar Bazz", "foo", "Bar", "Baz") | | hour(useLocalTimeOrTimezone: boolean \| string) | Returns the current hour. | hour() >= 0 and hour() <= 23 | | isFalsy(val: any) | Checks if a value is falsy. | isFalsy(arg0) | | isNil(val: any) | Checks if a value is null or undefined. | isNil(arg0) | | isNull(val: any) | Checks if a value is null. | isNull(arg0) | | isoWeek(useLocalTimeOrTimezone: boolean \| string) | Returns the current ISO week. | isoWeek() >= 1 and isoWeek() <= 53 | | isoWeekday(useLocalTimeOrTimezone: boolean \| string) | Returns the current ISO weekday. | isoWeekday() >= 1 and isoWeekday() <= 7 | | isTruthy(val: any) | Checks if a value is truthy. | isTruthy(arg0) | | isUndefined(val: any) | Checks if a value is undefined. | isUndefined(arg0) | | item(arr: any, key: any = 0) | Returns the value of an array-like object. | item(args, 1) == "foo" | | join(seperator: any, ..args: any[]) | Handles a list of arguments as strings and joins them to one, using a separator. | join(" + ", "MK", "TM") == "MK + TM" | | len(val: any) | Returns the length of a value. | len("foo") == 3 and len(args) >= 1 | | log(val: any, returnValue: any = true) | Logs a value. | log(args) | | lower(val: any) | Handles a value as string and converts its characters to lowercase. | lower("FoO") == "foo" | | ltrim(val: any) | Handles a value as string and removes leading whitespace characters. | ltrim(" foo ") == "foo " | | minute(useLocalTimeOrTimezone: boolean \| string) | Returns the current minute. | minute() >= 0 and minute() <= 59 | | month(useLocalTimeOrTimezone: boolean \| string) | Returns the current month. | month() >= 1 and month() <= 12 | | ms(useLocalTimeOrTimezone: boolean \| string) | Returns the current milliseconds. | ms() >= 0 and ms() <= 999 | | now(useLocalTimeOrTimezone: boolean \| string) | Returns the UNIX timestamp of the current time. | log(now()) | | regex(val: any, pattern: string, flags: string = "i") | Handles a value as string and checks for a regular expression. | regex("Foo Bar Bazz", "(bar)") | | rtrim(val: any) | Handles a value as string and removes ending whitespace characters. | rtrim(" foo ") == " foo" | | second(useLocalTimeOrTimezone: boolean \| string) | Returns the current second. | second() >= 0 and second() <= 59 | | some(value: any, ...args: any[]) | Handles a value as string and checks if a least one argument is included. | some("bar FoO BAZZ", "FoO", "BAR", "baz") | | startOf(value: any, unit: string, useLocalTimeOrTimezone: boolean \| string) | Returns a value, which represents the start of a time area. | startOf(now(), "day") <= now() | | str(value: any) | Converts a value to a string, which is not null and not undefined. | str(0) == "0" | | trim(val: any) | Handles a value as string and removes leading and ending whitespace characters. | trim(" foo ") == "foo" | | typeOf(value: any) | Returns the type of a value. | log(typeOf(arg0)) and typeOf(args) == "array" and typeOf(null) == "null" and typeOf("foo") == "string" | | upper(val: any) | Handles a value as string and converts its characters to uppercase. | upper("fOo") == "FOO" | | year(useLocalTimeOrTimezone: boolean \| string) | Returns the current year. | year() == 1979 and month() == 9 and day() == 5 |

It is possible, to add or remove functions:

import log from "@egomobile/log";
import { withFilterExpression } from "@egomobile/log-filter";

const str = (val: any) => String(val);
const repeatStr = (val: any, count: number) => str(val).repeat(count);

const expression = 'repeatStr(arg0, 5) == "TM+MK TM+MK TM+MK TM+MK TM+MK "';

log.use(
  withFilterExpression(expression, {
    extraFunctions: {
      // new, custom function
      repeatStr,
      // overwrite existing function
      str,

      // remove these
      ltrim: undefined,
      rtrim: undefined,
    },
  })
);

// will log
log("TM+MK ");
// will not log
log("foo");

Credits

The module makes use of:

• Day.js
• Filtrex by Michal Grňo

Documentation

The API documentation can be found here.