DefinitelyTyped/types/lambda-log/lambda-log-tests.ts

import * as log from 'lambda-log';

const logMessage: log.LogMessage = log.log('customLevel', 'custom', {
    key: 'value',
});
logMessage.level;
logMessage.meta;
logMessage.tags;
logMessage.msg;
logMessage.value;
logMessage.log;
logMessage.toJSON(true);

log.info('info', { key: 'value' });
log.warn('warn', { key: 'value' });
log.error(new Error('This is an error'), { key: 'value' });
log.debug('debug', { key: 'value' });
log.assert(true, 'this will print');

const logInstance = new log.LambdaLog({
    dynamicMeta: (logMessage: log.LogMessage) => {
        return {
            value: logMessage.value,
        };
    },
    logHandler: console,
    levelKey: 'msg',
    messageKey: 'msg',
    tagsKey: '_tags',
});
logInstance.log('customLevel', 'custom', { key: 'value' });
logInstance.info('info', { key: 'value' });
logInstance.warn('warn', { key: 'value' });
logInstance.error(new Error('This is an error'), { key: 'value' });
logInstance.debug('debug', { key: 'value' });
logInstance.assert(true, 'this will print');