Unable to infer types from Typescript programs

[harshitgarg22]

I am trying to infer the types of variables from a Typescript program for my custom CodeQL analysis. I am not able to get any types however. Is this a bug in the QL (I can file a bug report if so) or am I doing something wrong? Attaching my code below.

import javascript

from Expr var
where 
var.getLocation().getFile().getBaseName() = "doSomething.ts" or
var.getLocation().getFile().getBaseName() = "doSomething.js"
select var, var.getLocation(), var.getType()

returns

| var | col1 | col2 |
+-----+------+------+

for the program doSomething.ts

// Define a type for a person
type Person = {
    name: string;
    age: number;
};

// Function to greet a person
function greet(person: Person): string {
    return `Hello, ${person.name}! You are ${person.age} years old.`;
}

// Create a person object
const person: Person = {
    name: "John",
    age: 30,
};

// Call the greet function and log the result
console.log(greet(person));

Note that if I run this query without the getType predicate,

I get:

|          var          |       col1        |
+-----------------------+-------------------+
| name                  | doSomething.ts:3  |
| age                   | doSomething.ts:4  |
| greet                 | doSomething.ts:8  |
| person                | doSomething.ts:8  |
| `Hello, ... s old.`   | doSomething.ts:9  |
| Hello,                | doSomething.ts:9  |
| person.name           | doSomething.ts:9  |
| person                | doSomething.ts:9  |
| name                  | doSomething.ts:9  |
| ! You are             | doSomething.ts:9  |
| person.age            | doSomething.ts:9  |
| person                | doSomething.ts:9  |
| age                   | doSomething.ts:9  |
|  years old.           | doSomething.ts:9  |
| person: ... : 30,\n}  | doSomething.ts:13 |
| person                | doSomething.ts:13 |
| {\n    n ... : 30,\n} | doSomething.ts:13 |
| name                  | doSomething.ts:14 |
| "John"                | doSomething.ts:14 |
| age                   | doSomething.ts:15 |
| 30                    | doSomething.ts:15 |
| console ... erson))   | doSomething.ts:19 |
| console.log           | doSomething.ts:19 |
| console               | doSomething.ts:19 |
| log                   | doSomething.ts:19 |
| greet(person)         | doSomething.ts:19 |
| greet                 | doSomething.ts:19 |
| person                | doSomething.ts:19 |

[rvermeulen]

Hi @harshitgarg22,

Thanks for your question. That is indeed odd. I notice we do have the TypeRef relation, but are indeed missing the Type relation. I will forward this to the JavaScript team to determine what is happening.

Will keep you posted.

[harshitgarg22]

Also, I noticed that Expr.qll says Has no result if the expression is in a JavaScript file or in a TypeScript file that was extracted without type information.

While creating the database, we used the extractor_option for skip_types set to true and false, we still get nothing in either case.

[rvermeulen]

To get type information you need a tsconfig.json file in the root of your project. Does your project have this? If not you can create one with tsc --init.

[harshitgarg22]

Thanks, adding the tsconfig.json fixes things! (Might be helpful to add to the docs for TS).