CODEWITHSUNDEEP
typescripttypescript-compiler-api
Hongbo Miao
Hongbo Miao

Reputation: 49814

How to know the declaration kind of symbol in TypeScript compiler?

I am trying to build a code analysis tool following the Compiler API.

Right now the app below can print out p, Person, age, walk.

But how to know Person is interface, walk is function, etc.? Thanks

// app.ts

import * as ts from 'typescript';

const userAppFile = './user-app.ts';
const apiFile = './api.d.ts';

const program = ts.createProgram([userAppFile, apiFile], ts.getDefaultCompilerOptions());
const checker = program.getTypeChecker();
const sourceFile = program.getSourceFile(userAppFile);

function printApi(node) {
  const symbol = checker.getSymbolAtLocation(node);

  if (symbol) console.log(symbol.name);

  ts.forEachChild(node, printApi);
}

printApi(sourceFile);

// api.d.ts

interface Person {
  age: number;
}

declare function walk(speed: number): void;

// user-app.ts

const p: Person = { age: 10 };
walk(3);

Upvotes: 1

Views: 1307

Answers (1)

Daniel Gaeta
Daniel Gaeta

Reputation: 794

You check the flags on the symbol.

I.e.:

if(symbol.flags & ts.SymbolFlags.Class) {
   // this symbol is a class 
} else if (symbol.flags & ts.SymbolFlags.Interface) {
   // this is an interface 
}

Upvotes: 1

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