If a map.has(x), then map.get(x) can't be undefined

[DaniBr]

Bug Report

🔎 map has undefined, if map has, map get undefined

🕗 v4.4.3 (latest, October 2021)

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about _________

⏯ Playground Link

Playground link with relevant code

💻 Code

const MathNum: Map<string, number> = new Map([
	[ 'π', 3.1415926536 ],
	[ 'e', 2.7182818284 ],
])

let c = 'e'
let n = 0

if (MathNum.has(c)) {
	n = MathNum.get(c) // here is the problem
}

🙁 Actual behavior

Yields an error: Type 'number | undefined' is not assignable to type 'number'.

🙂 Expected behavior

Shouldn't be any problem, because we already checked that the map contains the requested key.

[MartinJohns]

Duplicate of #30268. Used search terms: has get in:title

[jcalz]

Duplicate of #13086, #9619 search terms “map has type guard”

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.