1  import type { Level, Logger } from './types';
 2  
 3  export abstract class BaseLogger<Args extends unknown[] = unknown[]>
 4      implements Logger<Args>
 5  {
 6      constructor(protected readonly name: string) {}
 7  
 8      /**
 9       * Log a debug level message.
10       * Appropriate for verbose logging that explains steps/details of the inner state of
11       * a code unit.
12       *
13       * Example uses include in a size-constrain datastructure, logging when the size
14       * exceeds the threshold and elements are removed, or in a virtual scrolling
15       * component logging when a scroll event causes a new page of elements to be loaded.
16       *
17       * @param args Arguments to log (same as console.debug)
18       * @return empty string (for use in brackets {} in svelte components)
19       */
20      debug(...args: Args): string {
21          return this.log('debug', ...args);
22      }
23  
24      /**
25       * Log an info level message.
26       * Appropriate for informational messages that may be relevant to consumers of a code
27       * unit.
28       *
29       * Example uses include a router logging when transitions occur or a button logging
30       * clicks.
31       *
32       * @param args Arguments to log (same as console.info)
33       * @return empty string (for use in brackets {} in svelte components)
34       */
35      info(...args: Args): string {
36          return this.log('info', ...args);
37      }
38  
39      /**
40       * Log a warn level message.
41       * Appropriate for situations where state has been (or likely will be) corrupted or
42       * invariants have been broken.
43       *
44       * Example uses include a data structure warning when it is used before being fully
45       * initialized.
46       *
47       * @param args Arguments to log (same as console.warn)
48       * @return empty string (for use in brackets {} in svelte components)
49       */
50      warn(...args: Args): string {
51          return this.log('warn', ...args);
52      }
53  
54      /**
55       * Log an error message.
56       * Appropriate for thrown errors or situations where the apps breaks or has to
57       * engage in fallback behavior to avoid a more catastrophic failure.
58       *
59       * @param args Arguments to log (same as console.error)
60       * @return empty string (for use in brackets {} in svelte components)
61       */
62      error(...args: Args): string {
63          return this.log('error', ...args);
64      }
65  
66      protected abstract log(method: Level, ...args: Args): string;
67  }