How to generate code from AST typescript parser?

Question

After I read the Using the Compiler API article, I could get the AST from string-code.

But when I try to generate the code (by escodegen) from AST (not transpile it) to code I got an error:

Unknown node type: undefined

Is there a way to generate the ast to the code?

import * as fs from "fs";
import escodegen from "escodegen";
import * as ts from "typescript";

const code = `
 function foo() { }
`;

const node = ts.createSourceFile("x.ts", code, ts.ScriptTarget.Latest);

console.log({ node });

const x = escodegen.generate(node);

console.log({ x });

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Answer 1

You can do it by createPrinter and pass node to printNode.

Here working example:

const code = `
 function foo() { }
`;

const node = ts.createSourceFile("x.ts", code, ts.ScriptTarget.Latest);
const printer = ts.createPrinter({ newLine: ts.NewLineKind.LineFeed });

const result = printer.printNode(ts.EmitHint.Unspecified, node, node);
console.log(result); // function foo() { }

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