@aws-lambda-powertools/logger/lib/esm/formatter/LogItem.js

The logging package for the Powertools for AWS Lambda (TypeScript) library

import merge from 'lodash.merge';
/**
 * LogItem is a class that holds the attributes of a log item.
 *
 * It is used by {@link LogFormatter} to store the attributes of a log item and to add additional attributes to it.
 */
class LogItem {
    /**
     * The attributes of the log item.
     */
    attributes = {};
    /**
     * Constructor for LogItem.
     *
     * Attributes are added in the following order:
     * - Standard keys provided by the logger (e.g. `message`, `level`, `timestamp`)
     * - Persistent attributes provided by developer, not formatted (done later)
     * - Ephemeral attributes provided as parameters for a single log item (done later)
     *
     * @param params - The parameters for the LogItem.
     */
    constructor(params) {
        this.setAttributes(params.attributes);
    }
    /**
     * Add attributes to the log item.
     *
     * @param attributes - The attributes to add to the log item.
     */
    addAttributes(attributes) {
        merge(this.attributes, attributes);
        return this;
    }
    /**
     * Get the attributes of the log item.
     */
    getAttributes() {
        return this.attributes;
    }
    /**
     * Prepare the log item for printing.
     *
     * This operation removes empty keys from the log item, see {@link removeEmptyKeys | removeEmptyKeys()} for more information.
     */
    prepareForPrint() {
        this.attributes = this.removeEmptyKeys(this.getAttributes());
    }
    /**
     * Remove empty keys from the log item, where empty keys are defined as keys with
     * values of `undefined`, empty strings (`''`), or `null`.
     *
     * @param attributes - The attributes to remove empty keys from.
     */
    removeEmptyKeys(attributes) {
        const newAttributes = {};
        for (const key in attributes) {
            if (attributes[key] !== undefined &&
                attributes[key] !== '' &&
                attributes[key] !== null) {
                newAttributes[key] = attributes[key];
            }
        }
        return newAttributes;
    }
    /**
     * Replace the attributes of the log item.
     *
     * @param attributes - The attributes to set for the log item.
     */
    setAttributes(attributes) {
        this.attributes = attributes;
    }
}
export { LogItem };