Error Cause
The ES2022 error-options bag: `new Error(msg, { cause })` records why an error was raised, chaining the underlying failure. The cause is untyped (`any`): a string, a number, or another Error all round-trip, and it rides through throw/catch.
const low = new Error("disk read failed")
const high = new Error("config load failed", { cause: low })
console.log(high.message) // config load failed
console.log(high.cause instanceof Error) // true
console.log(String(high.cause)) // Error: disk read failed
const tagged = new TypeError("bad input", { cause: 42 })
console.log(tagged.cause, typeof tagged.cause) // 42 number
// A cause-less error reads undefined, as in Node.
console.log(new Error("plain").cause) // undefined
try {
throw high
} catch (e) {
console.log("caught:", (e as Error).message) // caught: config load failed
console.log("because:", String((e as Error).cause)) // because: Error: disk read failed
}View source on GitHubexamples/try_catch/error_cause.ts