@comake/skl-js-engine/dist/logger.js

Standard Knowledge Language Javascript Engine

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Logger = void 0;
const util_1 = require("util");
class Logger {
    constructor(isDebug, metadata, options) {
        this.isDebug = true;
        this.metadata = metadata;
        this.maxStringLength = options?.maxStringLength ?? 2000;
        this.maxArrayItems = options?.maxArrayItems ?? 10;
    }
    /**
     * Returns a singleton instance of the logger. The logger honours the DEBUG env variable unless
     * explicitly overridden via the `isDebug` parameter.
     */
    static getInstance(isDebug, metadata, options) {
        if (!Logger.instance) {
            // eslint-disable-next-line no-process-env
            const debugEnabled = isDebug ?? process.env.DEBUG === 'true';
            Logger.instance = new Logger(debugEnabled, metadata ?? {}, options);
        }
        return Logger.instance;
    }
    /**
     * Merges the given metadata with the existing metadata attached to the logger.
     */
    setMetadata(metadata) {
        this.metadata = { ...this.metadata, ...metadata };
    }
    getMetadataString() {
        if (!this.metadata || Object.keys(this.metadata).length === 0) {
            return undefined;
        }
        return JSON.stringify(this.metadata);
    }
    // ---------------------------------------------------------------------------
    // Public logging APIs
    // ---------------------------------------------------------------------------
    log(...args) {
        if (this.isDebug) {
            const metadataString = this.getMetadataString();
            const logArgs = metadataString ? [...this.formatArgs(args), metadataString] : this.formatArgs(args);
            // eslint-disable-next-line no-console
            console.log(...logArgs);
        }
    }
    error(...args) {
        if (this.isDebug) {
            const metadataString = this.getMetadataString();
            const logArgs = metadataString ? [...this.formatArgs(args), metadataString] : this.formatArgs(args);
            // eslint-disable-next-line no-console
            console.error(...logArgs);
        }
    }
    debug(...args) {
        if (this.isDebug) {
            const metadataString = this.getMetadataString();
            const logArgs = metadataString ? [...this.formatArgs(args), metadataString] : this.formatArgs(args);
            // eslint-disable-next-line no-console
            console.debug(...logArgs);
        }
    }
    // ---------------------------------------------------------------------------
    // Private helpers
    // ---------------------------------------------------------------------------
    /**
     * Applies safe formatting to every argument before it is passed to the console. Large strings are
     * truncated, large arrays/objects are abbreviated and circular references are handled gracefully
     * by `util.inspect`.
     */
    formatArgs(args) {
        return args.map((arg) => this.formatValue(arg));
    }
    formatValue(value) {
        try {
            if (typeof value === 'string') {
                return this.truncateString(value);
            }
            if (Array.isArray(value)) {
                return JSON.stringify(this.truncateArray(value));
            }
            if (typeof value === 'object' && value !== null) {
                // For objects we rely on util.inspect which gives us fine-grained control over depth,
                // array length and string length.
                return (0, util_1.inspect)(value, {
                    depth: 6,
                    maxArrayLength: this.maxArrayItems,
                    maxStringLength: this.maxStringLength,
                    breakLength: 120,
                    compact: false,
                    colors: true
                });
            }
            // Primitives, functions, etc. are returned as-is.
            return value;
        }
        catch (err) {
            // In the unlikely event that formatting fails, fall back to a best-effort stringify.
            // eslint-disable-next-line no-console
            console.warn('Logger: failed to format value', err);
            return String(value);
        }
    }
    truncateString(str) {
        if (str.length <= this.maxStringLength) {
            return str;
        }
        return `${str.slice(0, this.maxStringLength)}...(truncated ${str.length - this.maxStringLength} chars)`;
    }
    truncateArray(arr) {
        if (arr.length <= this.maxArrayItems) {
            return arr.map((item) => this.formatValue(item));
        }
        const displayedItems = arr.slice(0, this.maxArrayItems).map((item) => this.formatValue(item));
        return [...displayedItems, `...(truncated ${arr.length - this.maxArrayItems} items)`];
    }
}
exports.Logger = Logger;
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