microsoft / microsoft/TypeScript

Divide by zero Typechecking

Open
#21,955 14 comments 1 reaction 0 assignees View on GitHub

Nobody has claimed this yet.

In Discussion Suggestion
Dominant language
Go
Stars
111k
Forks
14.3k
Avg merge
2d 4h
Merged PRs (30d)
132

Description

We have type literals for numbers already and a strictNullCheck compiler option -- wouldn't it be awesome if we had a type guard again divide-by-zero errors? I'm building a game that involved a lot of math, computing intersections of lines and such. But what if a line is parallel? It would be cool if the compiler would suggest this as a type error.

function f(): number | 0 {
    return 0
}

const y = 100 / f()

TypeScript Version: 2.7.0-dev.201xxxxx

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

No source file, test, or entry point is named. First reproduce the example with typescript@next and examine how the type checker handles the number | 0 return type and division; done means the compiler consistently identifies a possibly zero divisor and reports an appropriate type error.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
compilers
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
30/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.