Missing Type Information

[RebeccaStevens]

Some functions exported by typescript are missing from the type definition file (typescript.d.ts).
For example, the function isAssignmentExpression is missing.

https://github.com/Microsoft/TypeScript/blob/a2205ad53d8f65a129a552b752d1e06fee3d41fc/src/compiler/utilities.ts#L3865-L3873

(The function exists in lib/typescript.js, but not in lib/typescript.d.ts)

TypeScript Version: 3.2.0-dev.201xxxxx

Search Terms:
Missing Type Information
isAssignmentExpression
typescript.d.ts

Code

import * as ts from "typescript";

function test(node: ts.Node): boolean {
  return ts.isAssignmentExpression(node);
}

Expected behavior:

The definitions for isAssignmentExpression (and the other missing functions) are included in typescript.d.ts

Actual behavior:

The definitions for isAssignmentExpression (and the other missing functions) are not included in typescript.d.ts

Playground Link:
http://www.typescriptlang.org/play/#src=import%20*%20as%20ts%20from%20%22typescript%22%3B%0D%0A%0D%0Afunction%20test(node%3A%20ts.Node)%3A%20boolean%20%7B%0D%0A%20%20return%20ts.isAssignmentExpression(node)%3B%0D%0A%7D

[ajafff]

That's because this function or one of its parent is marked as // @internal. Such declarations are not emitted in the declaration files. That means these functions are internal helpers that should not be used by other projects.
You might want to have a look at my library tsutils which offers a lot of similar helper functions.
Take the isAssignmentExpression for example:

import {isBinaryExpression, isAssignmentKind} from 'tsutils';

declare let node: ts.Node;

if (isBinaryExpression(node) && isAssignmentKind(node.operatorToken.kind)) {
  // do stuff
}

[RebeccaStevens]

I guess that makes sense. I'll definitely have a look into tsutils.

Just wondering why the function is exported in the first place if it is intended to be used internally only.

This seems inconsistent as functions like isVariableDeclaration are not maked as internal.

[typescript-bot]

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