errors — Go-Style Error Handling

Structured error creation, wrapping, inspection, and comparison. Inspired by Go's errors package with sentinel errors and Is()/As() patterns.

Creating Errors

import { newError, newErrorCode, newErrorKind, StdError } from "errors";

let e = newError("file not found");                // Simple message
let e = newErrorCode("timeout", CODE_TIMEOUT());   // With error code
let e = newErrorKind("denied", KIND_PERMISSION_DENIED()); // With semantic kind

Error Wrapping (Go 1.13+)

Add context to errors while preserving the original cause:

import { wrap, wrapf, unwrapMsg } from "errors";

let original = newError("connection refused");
let wrapped = wrap(original, "failed to connect to database");
// wrapped.msg = "failed to connect to database"
// wrapped retains original error code

let innerMsg = unwrapMsg(wrapped);

Error Comparison (Is / Equals)

import { is, equals, hasCode } from "errors";

let e = ErrNotFound();

is(e, CODE_NOT_FOUND());      // → true (match by code)
equals(e, ErrNotFound());     // → true (match by code + message)
hasCode(e, 1);                // → true

Sentinel Errors

Pre-defined common errors for fast comparison:

Constructor	Message	Code
ErrNotFound()	"not found"	1
ErrPermission()	"permission denied"	2
ErrTimeout()	"timeout"	3
ErrCanceled()	"canceled"	4
ErrClosed()	"closed"	5
ErrEOF()	"EOF"	6
ErrInvalidArg()	"invalid argument"	7
ErrNotSupported()	"not supported"	8
ErrExists()	"already exists"	9
ErrConnRefused()	"connection refused"	10

Error Joining (Go 1.20+)

import { join2, join3 } from "errors";
let combined = join2(err1, err2);   // Merge two errors
let combined = join3(e1, e2, e3);   // Merge three errors

Inspection

Function	Description
getMessage(err)	Get error message
getCode(err)	Get error code
getKind(err)	Get semantic kind
isWrapped(err)	Check if error wraps another
toString(err)	String representation