Typescript parsing error when there is ">=>" in source code

[Shenmin-Z]

Source code:

():Array<number>=>{return [1]}

When using esbuild:

❯ esbuild a.ts
 > a.ts: error: Expected "=>" but found ":"
    1 │ ():Array<number>=>{return [1]}
      ╵   ^

1 error

Problem seems to be gone when a space is added between > and =>

New source code:

():Array<number> =>{return [1]}
//              ^ add space here!

Result:

❯ esbuild a.ts
() => {
  return [1];
};

Thanks!

[evanw]

Thanks for the report. This was tripping up esbuild's TypeScript parser because the >= token was split into a > token and a = token because the > token is needed to close the type parameter list, but the = token was not being combined with the following > token to form a => token. To fix this, esbuild needs to expand the = token into the following characters if possible, which can result in a =>, ==, or === token. The fix for this will go out with the next release.