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simple-log-ts

npm install @inctasoft/simple-log-ts

• debug, info, warn, error and crit methods.
• JSON format, useful for log ingesting services
• Error, Map Set objects are trnsformed into JSON and also printed
• In case of circular references, output is still JSON, and the message property will contain a string with the value of util.inspect(data, ...inspectOptions). inspectOptions by default is {} but can be overwritten in Log's constructor
• Optional correlation_id can be passed to constructor. Useful for correlating logs from different services. Pass printCorrelation: false in Log's constructor to skip it.

Usage

• Empty config

import { Log } from "@inctasoft/simple-log-ts";

const log = new Log();
log.error("something hapened", new Error('some err msg'));

results in:

{"timestamp":"2023-10-11T21:50:47.405Z","level":"ERROR","message":"something hapened","correlation":"undefined","[Error]":{"stack":"Error: some err msg\n    at Object..(the err stack)","message":"some err msg"}}```

• Log complex objects, provide correlation_id

import { Log } from "@inctasoft/simple-log-ts";
process.env.LOGLEVEL = 'DEBUG' // default level is WARN, un-silence debug method
const log = new Log({ correlation_id: 'some_guid' });
log.debug({
    a: 1, b: 'xyz', my_set: new Set(['foo', 'bar']), nested: {
        my_arr: [
            'elem1',
            new Map([['mapKey', {
                prop1: 1,
                prop2: new Date()
            }]])]
    }
});

results in:

{"timestamp":"2023-10-12T00:14:44.139Z","level":"DEBUG","message":{"a":1,"b":"xyz","my_set":["foo","bar"],"nested":{"my_arr":["elem1",{"mapKey":{"prop1":1,"prop2":"2023-10-12T00:14:44.139Z"}}]}},"correlation":"some_guid"}

• If you are interested in which transformed objects were of Map or Set types, provide printMapSetTypes: true
• Error objects are always printed as {"[Error]": {stack:"...", message: "..."}}
• If you are not into using correlation_id, provide printCorrelation: false

import { Log } from "@inctasoft/simple-log-ts";

const log = new Log({ printMapSetTypes: true, printCorrelation: false});
log.error({
    a: 1, b: 'xyz', my_set: new Set(['foo', 'bar']), nested: {
        my_arr: [
            'elem1',
            new Map([['mapKey', {
                prop1: 1,
                prop2: new Date()
            }]])]
    }
}, new Error("oops something unexpected happened"));

results in:

{"timestamp":"2023-10-12T01:57:31.983Z","level":"ERROR","message":{"a":1,"b":"xyz","my_set":{"[Set]":["foo","bar"]},"nested":{"my_arr":["elem1",{"[Map]":{"mapKey":{"prop1":1,"prop2":"2023-10-12T01:57:31.983Z"}}}]}},"[Error]":{"stack":"Error: oops something unexpected happened\n    at Object..(the err stack)","message":"oops something unexpected happened"}}

• Circular reference handlig

import { Log } from "../src/log";

const obj: any = {};
obj.a = [obj];
obj.b = {};
obj.b.inner = obj.b;
obj.b.obj = obj;

new Log().warn(obj)

results in:

{"timestamp":"2023-10-14T05:59:48.714Z","level":"WARN","message":"<ref *1> {\n  a: [ [Circular *1] ],\n  b: <ref *2> { inner: [Circular *2], obj: [Circular *1] }\n}","correlation":"undefined"}

Log levels

| process.env.LOGLEVEL | active methods | notes | |---|---|---| | DEBUG| debug,info,warn,error,crit| | | INFO | info,warn,error,crit|| | WARN | warn,error,crit| default, if no LOGLEVEL is present | | ERROR| error,crit| Both crit and error use console.error and accept optional second Error argument | | SILENT (or any other value)| crit | Lets you silence all logs, if not using crit method(as it is always active, no matter of LOGLEVEL value) |